INTRODUCTION

TO THE READER

• This manual is written for an experienced technician • If you have any questions or comments, at if you
to provide technical information needed to maintain found any errors regarding the contents of this
and repair this machine. manual, please contact using “Service Manual
Revision Request Form at the end of this man-
• Be sure to thoroughly read this manual for correct ual.
product information and service procedures. (Note: Do not tear off the form. Copy it for us-
age.):
Publications Marketing & Product Support
Hitachi Construction Machinery Co. Ltd.
TEL: 81-298-32-7173
FAX: 81-298-31-1162

ADDITIONAL REFERENCES

• Please refer to the materials listed below in addition • Operation Manual of the Engine
to this manual. • Parts Catalog of the Engine
• Hitachi Training Material
• The Operator’s Manual
• The Parts Catalog

MANUAL COMPOSITION

• This manual consists of three portions: the Techni- • Information included in the Technical Manual
cal Manual (Operational Principle), the Technical (Troubleshooting):
Manual (Troubleshooting) and the Workshop Man- technical information needed for operational per-
ual. formance tests, and troubleshooting procedures.

• Information included in the Technical Manual • Information included in the Workshop Manual:
(Operational Principle): technical information needed for maintenance
technical information needed for redeliver and and repair of the machine, tools and devices
delivery, operation and activation of all devices needed for maintenance and repair, maintenance
and systems. standards, and removal/installation and assem-
ble/disassemble procedures.

PAGE NUMBER

• Each page has a number, located on the center

lower part of the page, and each number contains
the following information:

Example : T 1-3-5

Consecutive Page Number for Each Group

Group Number
Section Number
T: Technical Manual W: Workshop Manual

IN-01
 INTRODUCTION
SAFETY ALERT SYMBOL AND HEADLINE
NOTATIONS

In this manual, the following safety alert symbol and • CAUTION:

signal words are used to alert the reader to the Indicated potentially hazardous situation which
potential for personal injury of machine damage. could, if not avoided, result in personal injury or
death.
This is the safety alert symbol. When you see this
symbol, be alert to the potential for personal injury. • IMPORTANT:
Never fail to follow the safety instructions prescribed Indicates a situation which, if not conformed to the
along with the safety alert symbol. instructions, could result in damage to the machine.
The safety alert symbol is also used to draw attention
to component/part weights.
To avoid injury and damage, be sure to use appropri- • NOTE:
ate lifting techniques and equipment when lifting heavy Indicates supplementary technical information or
parts. know-how.

UNITS USED
2
• SI Units (International System of Units) are used in Example : 24.5 MPa (250 kgf/cm , 3560 psi)
this manual.
MKS system units and English units are also A table for conversion from SI units to other system
indicated in parenthheses just behind SI units. units is shown below for reference purposees.

To Convert To Convert
Quantity Into Multiply By Quantity Into Multiply By
From From
2
Length mm in 0.03937 Pressure MPa kgf/cm 10.197
mm ft 0.003281 MPa psi 145.0
L US gal 0.2642 Power kW PS 1.360
Volume L US qt 1.057 kW HP 1.341
3 3
m yd 1.308 Temperature °C °F °C×1.8+32
Weight kg lb 2.205 Velocity km/h mph 0.6214
-1
Force N kgf 0.10197 min rpm 1.0
N lbf 0.2248 Flow rate L/min US gpm 0.2642
Torque N⋅m kgf⋅m 1.0197 mL/rev cc/rev 1.0
N⋅m lbf⋅ft 0.7375

IN-02
 SAFETY
RECOGNIZE SAFETY INFORMATION

• This is the SAFETY ALERT SYMBOL.

• When you see this symbol on your machine or in
this manual, be alert to the potential for personal
injury.
• Follow recommended precautions and safe
operating practices.

001-E01A-0688

SA-688

UNDERSTAND SIGNAL WORDS

• On machine safety signs, signal words designating

the degree or level of hazard - DANGER, WARNING,
or CAUTION - are used with the safety alert symbol.
• DANGER indicates an imminently hazardous
situation which, if not avoided, will result in death
or serious injury.
• WARNING indicates a potentially hazardous
situation which, if not avoided, could result in
death or serious injury.
• CAUTION indicates a potentially hazardous
situation which, if not avoided, may result in minor
or moderate injury.
DANGER or WARNING safety signs are located
near specific hazards. General precautions are
listed on CAUTION safety signs.
• Some safety signs don’t use any of the
designated signal words above after the safety
alert symbol are occasionally used on this
machine.
• CAUTION also calls attention to safety messages in
this manual. SA-1223
• To avoid confusing machine protection with personal
safety messages, a signal word IMPORTANT
indicates a situation which, if not avoided, could
result in damage to the machine.

• NOTE indicates an additional explanation for an

element of information.
002-E01C-1223

SA-1
 SAFETY
FOLLOW SAFETY INSTRUCTIONS
• Carefully read and follow all safety signs on the
machine and all safety messages in this manual.
• Safety signs should be installed, maintained and re-
placed when necessary.
• If a safety sign or this manual is damaged or
missing, order a replacement from your author-
ized dealer in the same way you order other
replacement parts (be sure to state machine
model and serial number when ordering).
• Learn how to operate the machine and its controls
correctly and safely.
• Allow only trained, qualified, authorized personnel to SA-003

operate the machine.

• Keep your machine in proper working condition.
• Unauthorized modifications of the machine may
impair its function and/or safety and affect ma-
chine life.
• The safety messages in this SAFETY chapter are
intended to illustrate basic safety procedures of
machines. However it is impossible for these safety
messages to cover every hazardous situation you
may encounter. If you have any questions, you
should first consult your supervisor and/or your au-
thorized dealer before operating or performing
maintenance work on the machine.
003-E01B-0003

SA-2
 SAFETY
PREPARE FOR EMERGENCIES
• Be prepared if a fire starts or if an accident occurs.
• Keep a first aid kit and fire extinguisher on hand.
• Thoroughly read and understand the label at-
tached on the fire extinguisher to use it properly.
• To ensure that a fire-extinguisher can be always
used when necessary, check and service the
fire-extinguisher at the recommended intervals as
specified in the fire-extinguisher manual.
• Establish emergency procedure guidelines to
cope with fires and accidents.
• Keep emergency numbers for doctors, ambu-
lance service, hospital, and fire department SA-437

posted near your telephone.

004-E01A-0437

WEAR PROTECTIVE CLOTHING

• Wear close fitting clothing and safety equipment
appropriate to the job.
You may need:
A hard hat
Safety shoes
Safety glasses, goggles, or face shield
Heavy gloves
Hearing protection
Reflective clothing
Wet weather gear
Respirator or filter mask. SA-438
Be sure to wear the correct equipment and clothing
for the job. Do not take any chances.
• Avoid wearing loose clothing, jewelry, or other
items that can catch on control levers or other
parts of the machine.
• Operating equipment safely requires the full
attention of the operator. Do not wear radio or music
headphones while operating the machine.

005-E01A-0438

SA-3
 SAFETY
PROTECT AGAINST NOISE
• Prolonged exposure to loud noise can cause
impairment or loss of hearing.
• Wear a suitable hearing protective device such as
earmuffs or earplugs to protect against
objectionable or uncomfortably loud noises.

006-E01A-0434

SA-434

INSPECT MACHINE

• Inspect your machine carefully each day or shift by

walking around it before you start it to avoid
personal injury.
• In the walk-around inspection be sure to cover all
points described in the “PRE-START
INSPECTION” chapter in the operator’s manual.

S007-E01A-0435

SA-435

SA-4
 SAFETY
GENERAL PRECAUTIONS FOR CAB
• Before entering the cab, thoroughly remove all
dirt and/or oil from the soles of your work boots. If
any controls such as a pedal is operated while
with dirt and/or oil on the soles of the operator’s
work boots the operator’s foot may slip off the
pedal, possibly resulting in a personal accident.
• Don’t leave parts and/or tools lying around the
operator’s seat. Store them in their specified loca-
tions.
• Avoid storing transparent bottles in the cab. Don’t
attach any transparent type window decorations
on the windowpanes as they may focus sunlight,
possibly starting a fire.
• Refrain from listening to the radio, or using music
headphones or mobile telephones in the cab
while operating the machine.
• Keep all flammable objects and/or explosives
away from the machine.
• After using the ashtray, always cover it to extin-
guish the match and/or tobacco.
• Don’t leave cigarette lighters in the cab. When the
temperature in the cab increases, the lighter may
explode.
524-E01A-0000

SA-5
 SAFETY
USE HANDHOLDS AND STEPS
• Falling is one of the major causes of personal injury.
• When you mounting and dismounting the ma-
chine, always face the machine and maintain a
three-point contact with the steps and handrails.
• Do not use any controls as hand-holds.
• Never jump on or off the machine. Never mount
or dismount a moving machine.
• Be careful of slippery conditions on platforms,
steps, and handrails when mounting and dis-
mounting the machine.
SA-439

008-E01B-0439

ADJUST THE OPERATOR'S SEAT

• A poorly adjusted seat for either the operator or for

the work at hand may quickly fatigue the operator
leading to misoperations.
• The seat should be adjusted whenever changing
the operator for the machine.
• The operator should be able to fully depress the
pedals and to correctly operate the control levers
with his back against the seat back.
• If not, move the seat forward or backward, and
check again.
SA-378

009-E01A-0378

SA-6
 SAFETY
FASTEN YOUR SEAT BELT
• If the machine should overturn, the operator may
become injured and/or thrown from the cab.
Additionally the operator may be crushed by the
overturning machine, resulting in serious injury or
death.
• Prior to operating the machine, thoroughly
examine webbing, buckle and attaching hardware.
If any item is damaged or worn, replace the seat
belt or component before operating the machine.
• Be sure to remain seated with the seat belt
securely fastened at all times when the machine SA-237
is in operation to minimize the chance of injury
from an accident.
• We recommend that the seat belt be replaced
every three years regardless of its apparent
condition.

010-E01A-0237

MOVE AND OPERATE MACHINE SAFELY

• Bystanders can be run over.
• Take extra care not to run over bystanders.
Confirm the location of bystanders before moving,
swinging, or operating the machine.
• Always keep the travel alarm and horn in working
condition (if equipped). It warns people when the
machine starts to move.
• Use a signal person when moving, swinging, or
operating the machine in congested areas.
Coordinate hand signals before starting the
machine. SA-426

011-E01A-0426

SA-7
 SAFETY
OPERATE ONLY FROM OPERATOR'S
SEAT
• Inappropriate engine starting procedures may cause
the machine to runaway, possibly resulting in
serious injury or death.
• Start the engine only when seated in the
operator's seat.
• NEVER start the engine while standing on the
track or on ground.
• Do not start engine by shorting across starter
terminals.
• Before starting the engine, confirm that all control SA-444
levers are in neutral.

012-E01B-0444

JUMP STARTING
• Battery gas can explode, resulting in serious injury.
• If the engine must be jump started, be sure to
follow the instructions shown in the “OPERATING
THE ENGINE” chapter in the operator’s manual.
• The operator must be in the operator’s seat so
that the machine will be under control when the
engine starts. Jump starting is a two-person
operation.
• Never use a frozen battery.
• Failure to follow correct jump starting procedures
could result in a battery explosion or a runaway SA-032
machine.

S013-E01A-0032

SA-8
 SAFETY
KEEP RIDERS OFF MACHINE
• Riders on machine are subject to injury such as
being struck by foreign objects and being thrown off
the machine.
• Only the operator should be on the machine.
Keep riders off.
• Riders also obstruct the operator’s view, resulting
in the machine being operated in an unsafe
manner.

014-E01B-0379
SA-379

PROVIDE SIGNALS FOR FOBS INVOLV-

ING MULTIPLE NUMBERS OF MACHINES

• For jobs involving multiple numbers of machines,

provide signals commonly known by all personnel
involved. Also, appoint a signal person to coordinate
the job site. Make sure that all personnel obey the
signal person’s directions.

018-E01A-0481
SA-481

CONFIRM DIRECTION OF MACHINE TO

BE DRIVEN

• Incorrect travel pedal/lever operation may result in

serious injury death.
• Before driving the machine, confirm the position
of the undercarriage in relation to the operator’s
position. If the travel motors are located in front of
the cab, the machine will move in reverse when
travel pedals/levers are operated to the front.

017-E01A-0491
SA-491

SA-9
 SAFETY
DRIVE MACHINE SAFELY
• Before driving the machine, always confirm that the
travel levers/pedals direction corresponds to the
direction you wish to drive.
• Be sure to detour around any obstructions.
• Avoid traveling over obstructions. Soil, fragments
of rocks, and/or metal pieces may scatter around
the machine. Don’t allow personnel to stay
around the machine while traveling.

SA-387

• Driving on a slope may cause the machine to slip or

overturn, possibly resulting in serious injury or
death.
• When driving up or down a slope, keep the
bucket facing the direction of travel, approxi-
mately 200 to 300 mm (A) above the ground.
• If the machine starts to skid or becomes unstable,
immediately lower the bucket to the ground and
stop traveling.

SA-388

• Driving across the face of a slope or steering on a SA-441

slope may cause the machine to skid or turnover.

If the direction must be changed, move the ma-
WRONG
chine to level ground, then, change the direction
to ensure sage operation.

019-E01D-0492

SA-590

SA-10
 SAFETY
AVOID INJURY FROM ROLLAWAY
ACCIDENTS
• Death or serious injury may result if you attempt to
mount or stop a moving machine.

To avoid rollaways:
• Select level ground when possible to park
machine.
• Do not park the machine on a grade.
• Lower the bucket and/or other work tools to the
ground.
• Turn the auto-idle / acceleration seleclter and the SA-391
H/P mode switch off.
• Run the engine at slow idle speed without load for
5 minutes to cool down the engine.
• Stop the engine and remove the key from the key
switch.
• Pull the pilot control shut-off lever to LOCK
position.
• Block both tracks and lower the bucket to the
ground. Thrust the bucket teeth into the ground if
you must park on a grade.
• Position the machine to prevent rolling.
• Park a reasonable distance from other machines.
SA-392

020-E08A-0493

SA-11
 SAFETY
AVOID INJURY FROM BACK-OVER AND
SWING ACCIDENTS
• If any person is present near the machine when
backing or swinging the upperstructure, the
machine may hit or run over that person, resulting in
serious injury or death.

To avoid back-over and swing accidents:

• Always look around BEFORE YOU BACK UP
AND SWING THE MACHINE. BE SURE THAT
ALL BYSTANDERS ARE CLEAR.
• Keep the travel alarm in working condition (if SA-383
equipped).
ALWAYS BE ALERT FOR BYSTANDERS
MOVING INTO THE WORK AREA. USE THE
HORN OR OTHER SIGNAL TO WARN
BYSTANDERS BEFORE MOVING MACHINE.
• USE A SIGNAL PERSON WHEN BACKING UP
IF YOUR VIEW IS OBSTRUCTED. ALWAYS
KEEP THE SIGNAL PERSON IN VIEW.
Use hand signals, which conform to your local
regulations, when work conditions require a signal
person.
• No machine motions shall be made unless
signals are clearly understood by both signalman SA-384

and operator.
• Learn the meanings of all flags, signs, and
markings used on the job and confirm who has
the responsibility for signaling.
• Keep windows, mirrors, and lights clean and in
good condition.
• Dust, heavy rain, fog, etc., can reduce visibility. As
visibility decreases, reduce speed and use proper
lighting.
• Read and understand all operating instructions in
the operator’s manual.

S021-E01A-0494

SA-12
 SAFETY
AVOID TIPPING
DO NOT ATTEMPT TO JUMP CLEAR OF
TIPPING MACHINE---SERIOUS OR FATAL
CRUSHING INJURIES WILL RESULT

MACHINE WILL TIP OVER FASTER THAN YOU

CAN JUMP FREE

FASTEN YOUR SEAT BELT

• The danger of tipping is always present when

operating on a grade, possibly resulting in serious SA-012
injury or death.

To avoid tipping:
• Be extra careful before operating on a grade.
• Prepare machine operating area flat.
• Keep the bucket low to the ground and close to
the machine.
• Reduce operating speeds to avoid tipping or
slipping.
• Avoid changing direction when traveling on
grades.
• NEVER attempt to travel across a grade steeper
than 15 degrees if crossing the grade is SA-440

unavoidable.
• Reduce swing speed as necessary when
swinging loads.
• Be careful when working on frozen ground.
• Temperature increases will cause the ground to
become soft and make ground travel unstable.

S025-E01B-0495

SA-13
 SAFETY
AVOID POWER LINES
• Serious injury or death can result if the machine or
front attachments are not kept a safe distance from
electric lines.
• When operating near an electric line, NEVER
move any part of the machine or load closer than
3 m (10 ft) plus twice the line insulator length.
• Check and comply with any local regulations that
may apply.
• Wet ground will expand the area that could cause
any person on it to be affected by electric shock.
Keep all bystanders or co-workers away from the
site.
SA-381

029-E01A-0381

OBJECT HANDLING
• If a lifted load should fall, any person nearby may be
struck by the falling load or may be crushed
underneath it, resulting in serious injury or death.
• When using the machine for craning operations,
be sure to comply with all local regulations.
• Do not use damaged chains or frayed cables,
sables, slings, or ropes.
• Before craning, position the upperstructure with
the travel motors at the rear.
• Move the load slowly and carefully. Never move it
suddenly.
• Keep all persons well away from the load.
• Never move a load over a person's head.
• Do not allow anyone to approach the load until it
is safely and securely situated on supporting
SA-014
blocks or on the ground.
• Never attach a sling or chain to the bucket teeth.
They may come off, causing the load to fall.

032-E01A-0014

SA-14
 SAFETY
PROTECT AGAINST FLYING DEBRIS
• If flying debris hit eyes or any other part of the body,
serious injury may result.
• Guard against injury from flying pieces of metal or
debris; wear goggles or safety glasses.
• Keep bystanders away from the working area
before striking any object.

031-E01A-0432
SA-432

PARK MACHINE SAFELY

To avoid accidents:
• Park machine on a firm, level surface.
• Lower bucket to the ground.
• Turn auto-idle / acceleration selector and H/P
mode switch off.
• Run engine at slow idle speed without load for 5
minutes.
• Turn key switch to OFF to stop engine.
• Remove the key from the key switch.
• Pull the pilot control shut-off lever to the LOCK
position. SA-390
• Close windows, roof vent, and cab door.
• Lock all access doors and compartments.

033-E09B-0390

SA-15
 SAFETY
HANDLE FLUIDS SAFELY－AVOID FIRES
• Handle fuel with care; it is highly flammable. If fuel
ignites, an explosion and/or a fire may occur,
possibly resulting in serious injury or death.
• Do not refuel the machine while smoking or when
near open flame or sparks.
• Always stop the engine before refueling the
machine.
• Fill the fuel tank outdoors.

• All fuels, most lubricants, and some coolants are

flammable. SA-018
• Store flammable fluids well away from fire
hazards.
• Do not incinerate or puncture pressurized
containers.
• Do not store oily rags; they can ignite and burn
spontaneously.
• Securely tighten the fuel and oil filler cap.

034-E01A-0496

SA-019

SA-16
 SAFETY
SAFETY TRANSPORTING
• The danger of tipping is present when
loading/unloading the machine onto/from a truck or
trailer bed.
• Be sure to observe local regulations when
transporting the machine on public roads.
• Provide an appropriate truck or trailer for
transporting the machine.

Take the following precautions when loading /

unloading the machine:
1) Select firm level ground. SA-395
2) Be sure to use a loading dock or ramp.
3) Be sure to have a signal person when
loading/unloading the machine.
4) Always turn the auto-idle / acceleration selector
and the H/P mode switch OFF when loading or
unloading the machine, to avoid unexpected
speed increase due to unintentional operation of
a control lever.
5) Always select the slow speed mode with the
travel mode switches. In the high speed mode,
travel speed may automatically increase.
6) Avoid steering while driving up or down the
ramp as it is extremely dangerous. If steering is
unavoidable, first move back to the ground or
flatbed, modify traveling direction, and begin to
drive again.
7) Do not operate any levers besides the travel
levers when driving up or down the ramp.
8) The top end of the ramp where it meets the
flatbed is a sudden bump. Take care when
traveling over it.
9) Prevent possible injury from machine tipping
while the upperstructure is rotating.
10) Keep the arm tucked under and rotate the
upperstructure slowly for best stability.
11) Securely fasten chain or cables to the machine
frame. Refer to "transporting" chapter in the
operator's manual for details.

S035-E08A-0395

SA-17
 SAFETY
PRACTICE SAFE MAINTENANCE
To avoid accidents:

• Understand service procedures before doing

work.
• Keep work area clean and dry.
• Do not spray water or steam inside cab.
• Never lubricate or service the machine while it is
moving.
• Keep hands, feet and clothing away from
power-driven parts.

• Before servicing the machine:

1) Park the machine on a level surface.
2) Lower the bucket to the ground.
3) Turn the auto-idle / acceleration selecltor off.
4) Run the engine at slow idle speed without load
for 5 minutes.
5) Turn the key switch to OFF to stop engine.
6) Relieve the pressure in the hydraulic system by
moving the control levers several times.
7) Remove the key from the switch.
8) Attach a “Do Not Operate” tag on the control
lever.
9) Pull the pilot control shut-off lever to the LOCK
position.
10) Allow the engine to cool.

SA-18
 SAFETY
• If a maintenance procedure must be performed
with the engine running, do not leave machine
unattended.
• If the machine must be raised, maintain a 90 to
110 angle between the boom and arm. Securely
support any machine elements that must be
raised for service work.
• Never work under a machine raised by the boom.
• Inspect certain parts periodically and repair or
replace as necessary. Refer to the section
discussing that part in the “MAINTENANCE”
chapter in the operator’s manual.
• Keep all parts in good condition and properly
installed.
• Fix damage immediately. Replace worn or broken
parts. Remove any buildup of grease, oil, or
debris.
• When cleaning parts, always use nonflammable
SA-028
detergent oil. Never use highly frammable oil
such as fuel oil and gasoline to clean parts or
surfaces.
• Disconnect battery ground cable (-) before
making adjustments to electrical systems or
before welding on the machine.
• Illuminate your work area adequately but safely.
• Use a portable safety light for working inside or
under the machine.
• Make sure that the bulb is enclosed by a wire
cage.
The hot filament of an accidentally broken bulb
can ignite spilled fuel or oil.
• Sufficiently illuminate the work site. Use a
maintence work light when working under or SA-527

inside the machine.

• Always use a work light protected with a guard. In
case the light bulb is broken, spilled fuel, oil
antifreeze fluid, or window washer fluid may catch
fire.

S500-E02B-0497

SA-037

SA-19
 SAFETY
WARN OTHERS OF SERVICE WORK
• Unexpected machine movement can cause serious
injury.
• Before performing any work on the machine,
attach a “Do Not Operate” tag on the control
lever.

S501-E01A-0287

SA-287

SUPPORT MACHINE PROPERLY

• Never attempt to work on the machine without

securing the machine first.
• Always lower the attachment to the ground before
you work on the machine.
• If you must work on a lifted machine or
attachment, securely support the machine or
attachment. Do not support the machine on
cinder blocks, hollow tires, or props that may
crumble under continuous load. Do not work
under a machine that is supported solely by a
SA-527
jack.
519-E01A-0527

STAY CLEAR OF MOVING PARTS

• Entanglement in moving parts can cause serious
injury.
• To prevent accidents, care should be taken to
ensure that hands, feet, clothing, jewelry and hair
do not become entangled when working around
rotating parts.

502-E01A-0026

SA-026

SA-20
 SAFETY
PREVENT PARTS FROM FLYING
• Grease in the track adjuster is under high pressure.
Failure to follow the precautions below may result in
serious injury, blindness, or death.
• Do not attempt to remove GREASE FITTING or
VALVE ASSEMBLY.
• As pieces may fly off, be sure to keep body and
face away from valve.
• Travel reduction gears are under pressure.
• As pieces may fly off, be sure to keep body and
face away from AIR RELEASE PLUG to avoid
injury. GEAR OIL is hot. SA-344
• Wait for GEAR OIL to cool, then gradually loosen
AIR RELEASE PLUG to release pressure.

503-E01B-0344

STORE ATTACHMENTS SAFELY

• Stored attachments such as buckets, hydraulic
hammers, and blades can fall and cause serious
injury or death.
• Securely store attachments and implements to
prevent falling. Keep children and bystanders
away from storage areas.

504-E01A-0034 SA-034

USE TOOLS PROPERLY

• Use tools appropriate for the work to be done.
• Makeshift tools, parts, and procedures can create
safety hazards.
• For loosening and tightening hardware, use the
correct size tools to avoid injury caused by
slipping wrenches.
• Use only recommended replacement parts.
(See the parts catalog.)

SA-040
S522-E01A-0040

SA-21
 SAFETY
PREVENT BURNS
Hot spraying fluids:
• After operation, engine coolant is hot and under
pressure. Hot water or steam is contained in the
engine, radiator and heater lines.
Skin contact with escaping hot water or steam can
cause severe burns.
• To avoid possible injury from hot spraying water.
DO NOT remove the radiator cap until the engine
is cool. When opening, turn the cap slowly to the
stop. Allow all pressure to be released before
removing the cap. SA-039
• The hydraulic oil tank is pressurized. Again, be
sure to release all pressure before removing the
cap.

Hot fluids and surfaces:

• Engine oil, gear oil and hydraulic oil also become
hot during operation.
The engine, hoses, lines and other parts become
hot as well.
• Wait for the oil and components to cool before
starting any maintenance or inspection work.

505-E01B-0498 SA-225

REPLACE RUBBER HOSES

PERIODICALLY

• Rubber hoses that contain flammable fluids under

pressure may break due to aging, fatigue, and
abrasion. It is very difficult to gauge the extent of
deterioration due to aging, fatigue, and abrasion of
rubber hoses by inspection alone.
• Periodically replace the rubber hoses. (See the
page of “Periodic replacement of parts” in the
operator’s manual.)
• Failure to periodically replace rubber hoses may
cause a fire, fluid injection into skin, or the front SA-019
attachment to fall on a person nearby, which may
result in severe burns, gangrene, or otherwise
serious injury or death.

S506-E01A-0019

SA-22
 SAFETY
AVOID HIGH-PRESSURE FLUIDS
• Fluids such as diesel fuel or hydraulic oil under
pressure can penetrate the skin or eyes causing
serious injury, blindness or death.
• Avoid this hazard by relieving pressure before
disconnecting hydraulic or other lines.
• Tighten all connections before applying pressure.
• Search for leaks with a piece of cardboard; take
care to protect hands and body from
high-pressure fluids. Wear a face shield or SA-031

goggles for eye protection.

• If an accident occurs, see a doctor familiar with
this type of injury immediately. Any fluid injected
into the skin must be surgically removed within a
few hours or gangrene may result.

SA-292

507-E03A-0499

SA-044

SA-23
 SAFETY
PREVENT FIRES
Check for Oil Leaks:
• Fuel, hydraulic oil and lubricant leaks can lead to
fires.
• Check for oil leaks due to missing or loose
clamps, kinked hoses, lines or hoses that rub
against each other, damage to the oil-cooler, and
loose oil-cooler flange bolts.
• Tighten, repair or replace any missing, loose or
damaged clamps, lines, hoses, oil-cooler and
oil-cooler flange bolts.
• Do not bend or strike high-pressure lines.
• Never install bent or damaged lines, pipes, or SA-019
hoses.

Check for Shorts:

• Short circuits can cause fires.
• Clean and tighten all electrical connections.
• Check before starting work for loose, kinked,
hardened or frayed electrical cables and wires.
• Check before starting work for missing or
damaged terminal caps.
• DO NOT OPERATE MACHINE if cable or wires
are loose, kinked, etc..

Clean up Flammables:
• Spilled fuel and oil, and trash, grease, debris,
accumulated coal dust, and other flammables may
cause fires.
• Prevent fires by inspecting and cleaning the
machine daily and by removing spilled or
accumulated flammables immediately.

SA-24
 SAFETY
Check Key Switch:
• If a fire breaks out, failure to stop the engine will
escalate the fire, hampering fire fighting.
• Always check key switch function before
operating the machine every day:
1) Start the engine and run it at slow idle.
2) Turn the key switch to the OFF position to
confirm that the engine stops.
• If any abnormalities are found, be sure to repair
them before operating the machine.

Check Emergency Engine Stop Switch:

• If a fire breaks out, failure to release pressurized air
inside the hydraulic tank will escalate fire, hamper-
ing fire fighting.
• Check the emergency engine stop switch function
every 250 hours:
1) Start the engine and run it at slow Idle.
2) Turn the emergency engine stop switch to the
EMERG. STOP position.
3) Confirm that both engines stop and that
pressurized air inside the hydraulic oil tank is
released (a hissing sound should be heard).
• If any abnormalities are found, be sure to repair
them before operating the machine.

Check Heat Shields:

• Damaged or missing heat shields may lead to fires.
• Damaged or missing heat shields must be
repaired or replaced before operating the
machine.

S508-E02B-0019

SA-25
 SAFETY
EVACUATING IN CASE OF FIRE
• If a fire breaks out, evacuate the machine in the
following way:
• Stop the engine by turning the key switch to the
OFF position if there is time.
• Use a fire extinguisher if there is time.
• Exit the machine.

• In an emergency, if the cab door and/or the front SA-393

window cannot be opened, break the front or rear
window panes with the emergency evacuation
hammer to escape from the cab.
Refer to the explanation page on “EMERGENCY
EXIT” in Operator’s Manual.

518-E02B-0393

SS-1510

BEWARE OF EXHAUST FUMES

• Prevent asphyxiation. Engine exhaust fumes can
cause sickness or death.
• If you must operate in a building, be sure there is
adequate ventilation. Either use an exhaust pipe
extension to remove the exhaust fumes or open
doors and windows to bring enough outside air
into the area.

509-E01A-0016

SA-016

SA-26
 SAFETY
PRECAUTIONS FOR WELDING AND
GRINDING
• Welding may generate gas and/or small fires.
• Be sure to perform welding in a well ventilated
and prepared area. Store flammable objects in a
safe place before starting welding.
• Only qualified personnel should perform welding.
Never allow an unqualified person to perform
welding.
• Grinding on the machine may create fire hazards.
Store flammable objects in a safe place before
starting grinding.
• After finishing welding and grinding, recheck that SA-818

there are no abnormalities such as the area sur-

rounding the welded area still smoldering.
523-E01A-0818

AVOID HEATING NEAR PRESSURIZED

FLUID LINES
• Flammable spray can be generated by heating near
pressurized fluid lines, resulting in severe burns to
yourself and bystanders.
• Do not heat by welding, soldering, or using a
torch near pressurized fluid lines or other
flammable materials.
• Pressurized lines can be accidentally cut when
heat goes beyond the immediate flame area.
Install temporary fire-resistant guards to protect
hoses or other materials before engaging in
SA-030
welding, soldering, etc..

AVOID APPLYING HEAT TO LINES

CONTAINING FLAMMABLE FLUIDS
• Do not weld or flame cut pipes or tubes that
contain flammable fluids.
• Clean them thoroughly with nonflammable solvent
before welding or flame cutting them.
510-E01B-0030

SA-27
 SAFETY
REMOVE PAINT BEFORE WELDING OR
HEATING
• Hazardous fumes can be generated when paint is
heated by welding, soldering, or using a torch. If
inhaled, these fumes may cause sickness.
• Avoid potentially toxic fumes and dust.
• Do all such work outside or in a well-ventilated
area. Dispose of paint and solvent properly.

• Remove paint before welding or heating:

1) If you sand or grind paint, avoid breathing the
dust. SA-029
Wear an approved respirator.
2) If you use solvent or paint stripper, remove
stripper with soap and water before welding.
Remove solvent or paint stripper containers and
other flammable material from area. Allow
fumes to disperse at least 15 minutes before
welding or heating.

511-E01A-0029

PREVENT BATTERY EXPLOSIONS

• Battery gas can explode.

• Keep sparks, lighted matches, and flame away
from the top of battery.
• Never check battery charge by placing a metal
object across the posts. Use a voltmeter or hy-
drometer.
• Do not charge a frozen battery; it may explode.
Warm the battery to 16 °C ( 60 °F ) first.
• Do not continue to use or charge the battery
when electrolyte level is lower than specified. Ex-
plosion of the battery may result. SA-032
• Loose terminals may produce sparks. Securely
tighten all terminals.
• Battery electrolyte is poisonous. If the battery should
explode battery electrolyte may be splashed into
eyes, possibly resulting in blindness.
• Be sure to wear eye protection when checking
electrolyte specific gravity.

512-E01C-0032

SA-28
 SAFETY
SERVICE AIR CONDITIONING SYSTEM
SAFELY
• If spilled onto skin, refrigerant may cause a cold
contact burn.
• Refer to the freon container for proper use when
servicing the air conditioning system.
• Use a recovery and recycling system to avoid
venting freon into the atmosphere.
• Never let the freon stream make contact with the
skin.

SA-405
513-E01A-0405

HANDLE CHEMICAL PRODUCTS SAFELY

• Direct exposure to hazardous chemicals can cause

serious injury. Potentially hazardous chemicals used
with your machine include such items as lubricants,
coolants, paints, and adhesives.
• A Material Safety Data Sheet (MSDS) provides
specific details on chemical products: physical
and health hazards, safety procedures, and
emergency response techniques.
• Check the MSDS before you start any job using a
hazardous chemical. That way you will know
exactly what the risks are and how to do the job SA-309
safely. Then follow procedures and use
recommended equipment.

S515-E01A-0309

SA-29
 SAFETY
DISPOSE OF WASTE PROPERLY
• Improperly disposing of waste can threaten the
environment and ecology. Potentially harmful waste
used with HITACHI equipment includes such items
as oil, fuel, coolant, brake fluid, filters, and batteries.
• Use leakproof containers when draining fluids. Do
not use food or beverage containers that may
mislead someone into drinking from them.
• Do not pour waste onto the ground, down a drain,
or into any water source.
• Air conditioning refrigerants escaping into the air
can damage the Earth’s atmosphere. SA-226
Government regulations may require a certified
air conditioning service center to recover and
recycle used air conditioning refrigerants.
• Inquire on the proper way to recycle or dispose of
waste from your local environmental or recycling
center.

S516-E01A-0226

BEFORE RETURNING THE MACHINE TO

THE CUSTOMER
• After maintenance or repair work is complete,
confirm that:
• The machine is functioning properly, especially
the safety systems.
• Worn or damaged parts have been repaired or
replaced

S517-E01A-0435 SA-435

SA-30
 SECTION 4 OPERATIONAL PER-
FORMANCE TEST
SECTION AND GROUP
CONTENTS Group 1 Introduction
Group 2 Standard
Group 3 Engine Test
Group 4 Excavator Test
Group 5 Component Test
TECHNICAL MANUAL
Group 6 Adjustment
(Troubleshooting) SECTION 5 TROUBLESHOOTING
Group 1 General
Group 2 Component Layout
Group 3 Troubleshooting A
Group 4 Troubleshooting B
Group 5 Troubleshooting C
Group 6 Electrical System Inspection
Group 7 ICX
TECHNICAL MANUAL (Operational Principle)
SECTION 1 GENERAL SECTION 3 COMPONENT OPERATION
Group 1 Specifications Group 1 Pump Device
Group 2 Component Layout Group 2 Swing Device
Group 3 Component Specifications Group 3 Control Valve
SECTION 2 SYSTEM Group 4 Pilot Valve
Group 1 Control System Group 5 Travel Device
All information, illustrations and speci- Group 2 Hydraulic System Group 6 Signal Control Valve
fications in this manual are based on Group 3 Electrical System Group 7 Others (Upperstructure)
the latest product information available Group 8 Others (Undercarriage)
at the time of publication. The right is
reserved to make changes at any time
without notice. WORKSHOP MANUAL
SECTION 1 GENERAL INFORMA- SECTION 3 UNDERCARRIAGE
TION Group 1 Swing Bearing
Group 1 Precautions for Disassem- Group 2 Travel Device
bling and Assembling Group 3 Center Joint
Group 2 Tightening Torque Group 4 Track Adjuster
Group 3 Painting Group 5 Front Idler
COPYRIGHT(C)2002 SECTION 2 UPPERSTRUCTURE Group 6 Upper and Lower Roller
Hitachi Construction Machinery Co., Ltd. Group 1 Cab Group 7 Track
Tokyo, Japan Group 2 Counterweight SECTION 4 FRONT ATTACHMENT
All rights reserved Group 3 Main Frame Group 1 Front Attachment
Group 4 Pump Device Group 2 Cylinder
Group 5 Control Valve SECTION 5 ENGINE
Group 6 Swing Device
Group 7 Pilot Valve
Group 8 Pilot Shut-Off Valve
Group 9 Solenoid Valve
Group 10 Signal Control Valve
Group 11 Shockless Valve
 SECTION 4
OPERATIONAL
PERFORMANCE TEST

CONTENTS
Group 1 Introduction Dig Function Drift Check ....................... T4-4-13
Operational Performance Tests............. T4-1-1 Control Lever Operating Force.............. T4-4-14
Preparation for Performance Test ......... T4-1-2 Control Lever Stroke ............................. T4-4-15
Boom Raise/Swing Combined
Group 2 Standard Operation Check ................................. T4-4-16
Operational Performance
Standard Table.................................... T4-2-1 Group 5 Component Test
Main Pump P-Q Diagram ...................... T4-2-4 Primary Pilot Pressure .......................... T4-5-1
Injection Pump...................................... T4-2-5 Secondary Pilot Pressure...................... T4-5-3
Dr.EX Monitor Indicating Values............ T4-2-6 Main Relief Pressure Shift Control
Sensor Activating Range....................... T4-2-10 Pressure(SA Pressure) ....................... T4-5-4
Travel Mode Shift Control
Group 3 Engine Test Pressure(SB Pressure) ....................... T4-5-5
Engine Speed ....................................... T4-3-1 Boom Mode Selector Control
Engine Compression Pressure ............. T4-3-3 Pressure(SC Pressure) ....................... T4-5-6
Valve Clearance Adjustment ................. T4-3-4 Main Pump Delivery Pressure ............... T4-5-7
Nozzle Check ....................................... T4-3-6 Main Relief Pressure ............................ T4-5-8
Injection Timing .................................... T4-3-8 Overload Relief Valve Set Pressure ...... T4-5-12
Main Pump Flow Rate Measurement .... T4-5-14
Group 4 Excavator Test Swing Motor Drainage........................... T4-5-18
Travel Speed ........................................ T4-4-1 Travel Motor Drainage .......................... T4-5-20
Track Revolution Speed ........................ T4-4-2
Mistrack Check ..................................... T4-4-3 Group 6 Adjustment
Travel Motor Leakage ........................... T4-4-4 Installation and Adjustment
Swing Speed......................................... T4-4-5 of Pump Displacement Sensor ............ T4-6-1
Swing Function Drift Check................... T4-4-6 Engine Speed Adjustment and
Swing Motor Leakage ........................... T4-4-7 Engine Learning.................................. T4-6-2
Maximum Swingable Slant Angle .......... T4-4-8 Check of Governor Lever and
Swing Bearing Play............................... T4-4-9 Fuel Cut Lever Position....................... T4-6-4
Hydraulic Cylinder Cycle Time .............. T4-4-11

16JT-4-1
(Blank)

16JT-4-2
 OPERATIONAL PERFORMANCE TEST / Introduction
OPERATIONAL PERFORMANCE TESTS
Use operational performance test procedures to quan-
titatively check all systems and functions on the ma-
chine.

Purpose of Performance Tests Precautions for Evaluation of Test Data

1. To comprehensively evaluate each operational 1. To evaluate not only that the test data are correct,
function by comparing the performance test data but also in what range the test data are.
with the standard values.
2. Be sure to evaluate the test data based on the
2. According to the evaluation results, repair, adjust, machine operation hours, kinds and state of work
or replace parts or components as necessary to loads, and machine maintenance conditions.
restore the machine's performance to the desired
standard. The machine performance does not always deteriorate
as the working hours increase. However, the machine
3. To economically operate the machine under op- performance is normally considered to reduce in pro-
timal conditions. portion to the increase of the operation hours.
Accordingly, restoring the machine performance by
Kinds of Tests repair, adjustment, or replacement shall consider the
number of the machine's working hours.
1. Base machine performance test is to check the
operational performance of each system such as Definition of “Performance Standards”
engine, travel, swing, and hydraulic cylinders.
1. Operation speed values and dimensions of the
2. Hydraulic component unit test is to check the op- new machine.
erational performance of each component such
as hydraulic pump, motor, and various kinds of 2. Operational performance of new components
valves. adjusted to specification. Allowable errors will be
indicated as necessary.
Performance Standards

“Performance Standards” is shown in tables to evalu-

ate the performance test data.

T4-1-1
 OPERATIONAL PERFORMANCE TEST / Introduction
PREPARATION FOR PERFORMANCE
TESTS
Observe the following rules in order to carry out per-
formance tests accurately and safely.

1. THE MACHINE
Repair any defects and damage found, such as
oil or water leaks, loose bolts, cracks and so on,
before starting to test.

2. TEST AREA
(1) Select a hard, flat surface.
(2) Secure enough space to allow the machine
to run straight more than 20 m (65 ft 7 inch),
and to make a full swing with the front at- T105-06-01-003
tachment extended.
(3) If required, rope off the test area and provide
signboards to keep unauthorized personnel
away.

1. PRECAUTIONS
(1) Before starting to test, agree upon the sig-
nals to be employed for communication
among coworkers. Once the test is started,
be sure to communicate with each other us-
ing these signals, and to follow them without
fail.
(2) Operate the machine carefully and always
give first priority to safety.
(3) While testing, always take care to avoid ac- T105-06-01-003
cidents due to landslides or contact with
high-voltage power lines. Always confirm that
there is sufficient space for full swings.
(4) Avoid polluting the machine and the ground
with leaking oil. Use oil pans to catch escap-
ing oil. Pay special attention to this when
removing hydraulic pipings.

4. MAKE PRECISE MEASUREMENTS

(1) Accurately calibrate test instruments in ad-
vance to obtain correct data.
(2) Carry out tests under the exact test condi-
tions prescribed for each test item.
Repeat the same test and confirm that the
test data obtained can be procured repeat-
edly.
Use mean values of measurements if nec-
essary. T105-06-01-004

T4-1-2
 OPERATIONAL PERFORMANCE TEST / Standard
OPERATIONAL PERFORMANCE STAN-
DARD TABLE
The standard performance values are listed in the ta- test procedure:
ble below. Engine Control Dial : Fast Idle
Refer to the Group T4-3 to T4-4 for performance test Power Mode Switch : HP Mode
procedures. Auto-Idle/Acceleration Selector : OFF
Values indicated in parentheses are reference values. Work Mode Switch : Digging Mode
Hydraulic Oil Temperature : 50±5°C(122±9°F)

Performance
Performance Test Remarks
Standard
-1
ENGINE SPEED min
Slow Idle 900±100 Value indicated on Dr.EX
Fast Idle(HP mode) 1785±100 ↑
Fast Idle(E mode) 1780±100 ↑
Auto-Idle 1060±100 ↑
Fast Idle
1920±100 ↑
(HP mode Boom Relief Operation)
Fast Idle (Measured Value:1860 Reference
−
(HP mode Boom Lower Precision) Value)
ENGINE COMPRESSION PRESSURE Mpa(kgf/cm2) 2.75(28) After the engine warm-up
VALVE CLEARANCE (IN, EX) mm 0.4 With the engine cold
NOZZLE INJECTION PRESSURE Mpa(kgf/cm2) 20.1(205)
INJECTION TIMING (Degrees before TDC) deg. 10°
TRAVEL SPEED sec/20m
Fast Speed 13.0±2.0
Slow Speed 20.0±2.0
TRACK REVOLUTIO SPEED sec/3rev
Fast Speed 21.0±2.0
Slow Speed 31.0±2.0
MISTRACK mm/20m 200 or less
(With fast and travel speed modes)
TRAVEL MOTOR LEAKAGE mm/5 min 0
SWING SPEED sec/3rev 19.3±1.5 Bucket empty
SWING FUNCTION DRIFT CHECK mm/180° 1267 or less Bucket empty
SWING MOTOR LEAKAGE mm/5 min 0 Bucket loaded
MAXIMUM SWINGABLE SLANT ANGLE deg. 17 or more Bucket loaded
SWING BEARING PLAY mm 1.5 or less Allowable Limit : 5.0

T4-2-1
 OPERATIONAL PERFORMANCE TEST / Standard

Performance
Performance Test Remarks
Standard
HYDRAULIC CYLINDER CYCLE TIME sec
3.4 Arm
Backhoe 3
1.9 m Bucket, Bucket empty
Boom Raise 3.4±0.3
Boom Lower 2.5±0.3
Arm Roll-In 4.4±0..3
Arm Roll-Out 3.2±0.3
Bucket Roll-In 4.0±0.3
Bucket Roll-Out 2.8±0.3
3
Loading Shovel(Tentative) 2.6 m Bucket, Bucket empty
Boom Raise (4.5±0.3)
Boom Lower (3.6±0.3)
Arm Extend (2.7±0.3)
Arm Retract (2.0±0.3)
Bucket Roll-In (3.1±0.3)
Bucket Roll-Out (2.6±0.3)
Bucket Open (1.1±0.3)
Bucket Close (1.0±0.3)
DIG FUNCTION DRIFT CHECK mm/5min
3.4 Arm
3
Backhoe 1.9 m (PCSA heaped) Bucket,
Bucket loaded
Boom Cylinder 5 or less
Arm Cylinder 10 or less
Bucket Cylinder 10 or less
Bucket Bottom 100 or less
3
Loading Shovel (Tentative) 2.6 m Bucket, Bucket loaded
Boom Cylinder (40 or less)
Arm Cylinder (60 or less)
Bucket Cylinder (40 or less)
Bucket Bottom (100 or less)
CONTROL LEVER OPERATING FORCE N(kgf) Hitachi Lever Pattern
19.6 (2.0)
Boom Lever
or less
16.7 (1.7)
Arm Lever (ISO Lever Pattern: Swing Lever)
or less
16.7 (1.7)
Bucket Lever
or less
19.6 (2.0)
Swing Lever (ISO Lever Pattern: Arm Lever)
or less
24.5 (2.5)
Travel Lever
or less

T4-2-2
 OPERATIONAL PERFORMANCE TEST / Standard

Performance
Performance Test Remarks
Standard
CONTROL REVER STROKE mm Hitachi Lever Pattern
Boom Lever 105±10
Arm Lever (ISO Lever Pattern: Swing Lever) 83±10
Bucket Lever 83±10
Swing Lever (ISO Lever Pattern: Arm Lever) 105±10
Travel Lever 115±10
Backhoe : 3.4 m Arm
3
Boom Raise/Swing sec 5.0 or less 1.9 m (PCSA heaped) Bucket, Bucket
empty
Bucket Teeth Height: H mm 7000 or more
COMPONENT TEST
PRIMARY PILOT PRESSURE MPa(kgf/cm2)
+0.7
3.9 −0.2
Engine : Slow Idle +7.0
(39 −2.0)
+1.0
3.9 −0
Engine : Fast Idle +10
(39 −0)
MPa(kgf/cm2)
3.4 to 4.0
SECONDARY PILOT PRESSURE (Lever : Full Stroke)
(34 to 40)
SOLENOID VALVE SET PRESSURE MPa(kgf/cm2) Value indicated on Dr.EX
Main Relief Pressure Shift Control Pres-
3.5 more
sure
Travel Mode Shift Control Pressure 3.5 more
Boom Mode Selector Control Pressure 3.5 more
MAIN PUMP DELIVERY PRESSURE MPa(kgf/cm2)
MAIN RELIEF PRESSURE MPa(kgf/cm2) Value indicated on Dr.EX
When reliving Boom, Arm and Bucket
+2.5
30.4 −0
Standard +25
(310 −0)
+2.5
31.9 −0
Pressure Increase +25
(325 −0)
+2.0
27.9 −0
Swing +20
(280 −0)
+2.5
34.3 −0
Travel +25
(350 −0)
OVERLOAD RELIFE PRESSURE MPa(kgf/cm2) Value indicated on Dr.EX
+1.0
31.9 −0
Arm, Boom and Bucket +10
(325 −0)
+1.0
Boom (Lower) 9.8 −0
+10
(When operating Boom Mode Selector) (100 −0)
MAIN PUMP FLOW RATE L/min − Refer to page T4-2-5
SWING MOTOR DRAINAGE
0.2 to 0.3
With constant maximum speed
TRAVEL MOTOR DRAINAGE
5 or less Allowable Limit :10
With the track jacked up

T4-2-3
 OPERATIONAL PERFORMANCE TEST / Standard
MAIN PUMP P-Q DIAGRAM

• Hydraulic P-Q Control

Delivery Pressure Flow Rate
2
(REFERENCE: Measured at Test Stand) MPa (kgf/cm , psi) L/min (US gpm)
A 19.6 (200, 2840) Approx. 290 (77)
• Rated Pump Speed: 1800 min-1 (rpm)
• Target Pump Torque: 574 N⋅m (58.5 kgf⋅m) B 24.5 (250, 3560) Approx. 230 (61)

NOTE: Refer to T4-5-14.

L/min

Flow
Rate

Delivery Pressure MPa (kgf/cm2)

T16J-04-08-010

T4-2-4
 OPERATIONAL PERFORMANCE TEST / Standard
INJECTION PUMP
Test Conditions:
1. Nozzle assembly: 105780-8140
2. Nozzle: 105780-0000
3. Nozzle holder: 105780-2080
2
4. Nozzle opening pressure: 17.2 MPa (175 kgf/cm )
5. Test fuel: ISO 4113 or SAE J967d
2
6. Transfer pump pressure: 225 kPa (2.6 kgf/cm )
7. Injection pipe:
Inner Dia. 3 ×Outer Dia. 8 - Length 600 mm
(0.118×0.315×23.6 in)
8. Fuel temperature: 40 ±1 °C (104 ± 2 °F)

NOTE: The nozzle test injection pressure is 17.2

2
MPa (175 kgf/cm ). However, actual ma-
chine injection pressure is 20.1 MPa (205
2
kgf/cm ).

Maximum Variance
Pump Speed Rack Position Average Injec-
Strokes Between Cylinders Fixed Remarks
(min-1) (mm) tion Rate (cm3)
(%)
900 11.9 221 ± 2 ±3 Basic
450 6.6 9 ± 3.2 ± 13

Governor adjustment

T16J-04-08-009

T4-2-5
 OPERATIONAL PERFORMANCE TEST / Standard
DR. EX MONITOR INDICATING VALUES
Unless specified, test under the following conditions. ∗
NOTE: Items marked ( ) are measurable with the
Engine Speed: Fast Idle built-in diagnosing system.
Work Mode Switch: Digging Mode ∗∗
Items marked ( ) are measurable with the
Power Mode Switch: HP mode
built-in diagnosing system. However, it may
Auto-Idle/Acceleration Selector: OFF
be difficult to read the measured value
while operating the machine.

Reference Measured Value

Item Remarks
Value First Second Third Average
PUMP 1 PRESSURE (MPa)
∗
Control Lever in Neutral 0.8
∗
Boom Raise 32.1 When relieving
∗
Boom Lower -
∗
Arm Roll-in 32.1 When relieving
∗
Arm Roll-Out 32.1 When relieving
∗
Bucket Roll-Out 32.1 When relieving
Bucket Roll-In* 31.9 When relieving
Boom Raise + Arm
Roll-In + Bucket Roll-In 31.9 When relieving
∗
Combined Operation
PUMP 2 PRESSURE (MPa)
∗
Control Lever in Neutral 0.5
∗
Boom Raise 32.9 When relieving
∗
Boom Lower -
∗
Arm Roll-in 31.9 When relieving
∗
Arm Roll-Out 32.1 When relieving
∗
Bucket Roll-Out 0.8 When relieving
∗
Bucket Roll-In 32.1 When relieving
Boom Raise + Arm
Roll-In + Bucket Roll-In 31.9 When relieving
∗
Combined Operation
PUMP 1 DESIRED DIS-
PLACEMENT (cm3)
Control Lever in Neutral 52.8
Right Track Jacked-Up,
Right Travel Lever Full 204
Stroke
PUMP 2 DESIRED DIS-
PLACEMENT (cm3)
Control Lever in Neutral 54.4
Left Track Jacked-Up,
Left Travel Lever Full 204
Stroke

T4-2-6
 OPERATIONAL PERFORMANCE TEST / Standard

Reference Measured Value

Item Remarks
Value First Second Third Average
PUMP 1 PUMP CONTROL
PRESSURE (MPa)
Control Lever in Neutral∗ 0.97
Boom Raise∗ 4.33 When relieving
Boom Lower∗ -
Arm Roll-in∗ 4.33 When relieving
Arm Roll-Out∗ 3.75 When relieving
Bucket Roll-Out∗ 4.28 When relieving
Bucket Roll-In∗ 4.25 When relieving
Boom Raise + Arm Roll-In
+ Bucket Roll-In Combined 4.28 When relieving
Operation∗
PUMP 2 PUMP CONTROL
PRESSURE (MPa)
∗
Control Lever in Neutral 0.95
∗
Boom Raise 4.33 When relieving
∗
Boom Lower -
∗
Arm Roll-in 4.33 When relieving
∗
Arm Roll-Out 3.72 When relieving
∗
Bucket Roll-Out 1.00 When relieving
∗
Bucket Roll-In 0.97 When relieving
Boom Raise + Arm Roll-In
+ Bucket Roll-In Combined 4.28 When relieving
∗
Operation

T4-2-7
 OPERATIONAL PERFORMANCE TEST / Standard

Reference Measured Value

Item Remarks
Value First Second Third Average
TARGET ENGINE SPEED (min-1)
∗
Fast Idle (HP Mode) 1600
Fast Idle
∗ 1860
(When operating a control lever)
∗
Fast Idle (P Mode) 1600
∗
Fast Idle (E Mode) 1580
∗
Auto-Idle 1030
∗
Slow Idle 700
ACTUAL ENGINE SPEED (min-1)
∗
Fast Idle (HP Mode) 1830
Fast Idle
∗ 1930
(When operating a control lever)
∗
Fast Idle (P Mode) 1830
∗
Fast Idle (E Mode) 1810
∗
Auto-Idle 1260
∗
Slow Idle 920
ENGINE SPEED DEVIATION
(min-1)
∗
Fast Idle (HP Mode) 232
Fast Idle
∗ 134
(When operating a control lever)
∗
Fast Idle (P Mode) 232
∗
Fast Idle (E Mode) 236
∗
Auto-Idle 238
∗
Slow Idle 222
EC ANGLE (Volt)
∗
Minimum 2.49
∗
Maximum 3.20
DIAL ANGLE (Volt)
∗
Minimum 0.54
∗
Maximum 4.35

T4-2-8
 OPERATIONAL PERFORMANCE TEST / Standard

Reference Measured Value

Item Remarks
Value First Second Third Average
BOOM RAISE PILOT
∗ 4.34 When relieving
CONTROL PRESSURE (MPa)
ARM ROLL-IN PILOT
∗ 4.31 When relieving
CONTROL PRESSURE (MPa)
SWING PILOT CONTROL
∗ -
PRESSURE (MPa)
TRAVEL PILOT CONTROL
∗ 4.40
PRESSURE (MPa)
FRONT ATTACHMENT “ON-OFF” is dis-
∗ -
CONTROL PRESSURE (MPa) played
BOOM MODE CONTROL
PRESSURE (MPa)
Lever in Neutral 0
Boom Lower 3.92
POWER DIGGING CONTROL
PRESSURE (MPa)
During Operation 3.92
When Relieving Boom Raise
3.92
Circuit
TRAVEL MOTOR CONTROL Travel and Travel
PRESSURE (MPa) 3.92 Mode Switch
(Fast)
SWING and BOOM RAISE
CONTROL PRESSURE (MPa)
Swing and Boom Raise
3.92
Combined Operation

T4-2-9
 OPERATIONAL PERFORMANCE TEST / Standard
SENSOR ACTIVATING RANGE
1. Checking Method

• Hydraulic Oil Temperature: 50 ± 5 °C

• Unless specified:
Engine Power Auto-Idle/
Work Mode
Control Mode Auto-Acceleration
Switch
Dial Switch Selector
Maximum Digging
P Mode OFF
Speed Mode

• Monitor each sensor using Dr. EX.

2. Sensor Activating Range

Sensor Operation Specification

Minimum Speed 0.3 to 1.0 V
Engine Control Dial
Maximum Speed 4.0 to 4.7 V
Minimum Speed 2.5 to 2.7 V
Maximum Speed (HP Mode Switch: OFF) 3.3 to 3.7 V
EC Sensor
Maximum Speed (HP Mode Switch: ON) Maximum Speed
(Mode Switch: OFF) +0.2 V or more
2
Control Lever: Neutral 0 to 0.1 Mpa (0 to 1.0 kgf/cm )
Pilot Control Shut-Off Lever: LOCK
Pressure Sensor 2
Control Lever: Full Stroke 3.3 to 3.9 Mpa (34 to 40 kgf/cm )
Pilot Control Shut-Off Lever: UNLOCK
2
Pump Control Control Lever: Neutral 1.0 to 1.6 Mpa (10 to 16 kgf/cm )
2
Pressure Sensor Control Lever: Full Stroke 2.9 to 3.9 Mpa (30 to 40 kgf/cm )
3
Control Lever: Neutral *52.8 cm (3.255 V) (pump 1)
3
Pump Displacement *54.4 cm (1.697 V) (pump 2)
3
Angle Sensor One Track Jacked-Up, Travel Lever (Raised *204 cm
Track Side): Full Stroke
2
Pump Delivery Control Lever: Neutral *0.3 to 0.5 MPa (3 to5 kgf/cm )
+2.5 +25 2
Pressure Sensor Boom Raised and Cylinder Relieved 30.4 -0 MPa (304 -0 kgf/cm )
NOTE: *Reference Valve

T4-2-10
 OPERATIONAL PERFORMANCE TEST / Engine Test
ENGINE SPEED 2
1
Summary:
1. Measure engine speed using the built-in diag-
nosing system or Dr.EX. If the built-in diagnosing
system or Dr.EX is not available, use an engine
speed meter (refer to troubleshooting, Diagnosing
Procedure).
2. Measure the engine speeds in each mode.

NOTE: Measure the engine speed to check that

the engine speed meets specification be-
fore performing other operational perform-
ance tests. If the engine speed is not cor- T111-06-02-002
rectly adjusted, all other performance test
data will be unreliable.
3

Preparation:
1. Select the monitor function of built-in diagnosing
system or Dr. EX. When using an engine speed
meter, connect speed pick-up (1) to injection pipe
(2) as illustrated.
2. Warm up the engine until the engine coolant
temperature reaches 50 °C (122 °F) or more, and
hydraulic oil temperature reaches 50±5 °C (122±9
°F).

IMPORTANT: Be sure not to adjust stopper (3) on

the governor lever. T16J-04-02-008

T4-3-1
 OPERATIONAL PERFORMANCE TEST / Engine Test
Measurement: Evaluation:
1. Check engine speeds for auto-warm up (when Refer to T4-2 Operational Performance Standard.
starting the engine), auto-idle, slow idle, fast idle
(when normal), fast idle (in the E mode), and fast Remedy:
idle (in the HP mode). Refer to T5-4 Troubleshooting B.
2. Select the switch positions and the test conditions
corresponding to the engine speed to be meas-
ured as shown in the table below.
3. When using the pulse counter, read the pulse
counter. Calculate the engine speed using the
following formula:
-1
Engine Speed (min ) = Pulse Numbers (Hz) × 60
/ 139
Engine Power Auto-Idle/ Auto- Work
Control Mode Acceleration Mode Test Conditions
Dial Switch Selector Switch
Digging
Slow Idle Min. Speed HP OFF
Mode
Fast Idle (Nor- Digging
Max. Speed HP OFF
mal) Mode
Fast Idle (Relief Digging Check the engine speed while
Max. Speed HP OFF
operation) Mode relieving the boom raise circuit.
Fast Idle Digging
Max. Speed E Mode OFF
(E mode) Mode
Check engine speed 4 sec-
Digging
Auto-Idle Max. Speed HP Auto-Idle onds after returning all control
Mode
levers to neutral.

Monitor Panel Switch Panel

Engine Con-
trol Dial

Auto-Idle/ Accelera-
tion Selector

Power Mode
Switch

Work Mode
Switch

T178-01-01-004

M16J-01-010

T4-3-2
 OPERATIONAL PERFORMANCE TEST / Engine Test
ENGINE COMPRESSION PRESSURE
Summary:
1. Measure compression pressure in the cylinders to
check for a decline in engine power.

2. Check exhaust gas color and the amount of

blow-by gas from the crankcase. Keep track of
engine oil consumption.
Adapter T16J-04-02-002
3. Check for abnormalities in the intake system, in-
cluding the air filter.

Preparation:
1. Confirm that valve clearances are correct.

2. Confirm that the batteries are charged properly.

3. Run the engine until the coolant temperature

gauge reaches the operating range.

4. Stop the engine. Remove glow plugs from each

cylinder.

NOTE: Unless the fuel delivery pipes are discon-

nected, fuel will ignite in the cylinders so
T16J-04-02-001
that pressure in the cylinders will increase.

5. Install an adaptor (Isuzu 1-85317-019-0) and

compression gauge in place of the glow plug in
one cylinder. (Be sure to sufficiently tighten the
adaptor and compression gauge to prevent air
leakage.)

Measurement:
1. Turn the starter to crank the engine. Record the
compression pressure of each cylinder.

2. Repeat measurement three times for each cylin-

der and calculate the mean values.

Evaluation:
Refer to T4-2 in this section.

Remedy:
Refer to engine shop manual.

T4-3-3
 OPERATIONAL PERFORMANCE TEST / Engine Test
VALVE CLEARANCE ADJUSTMENT
Summary:
1. Perform the measurement when the engine is
cold.
2. Clean the head cover mounting area to avoid any
foreign matter from getting into the engine sys-
tem.

Pointer
Preparation:
1. Locate the top dead center (TC) in the compres-
sion stroke.
Remove the cover on the left bottom of the
fly-wheel housing.
Align the TC mark on the flywheel periphery with
the pointer located on the flywheel housing by ro-
tating the ring gear using a bar.
Piston No. 1 (or piston No. 6) is now at TC in its
compression stroke.
2. Remove the head cover.
T16J-04-02-003
3. Joggle the intake and exhaust side push rods of
cylinder No. 1 by hand. If they move a little, piston
No.1 is at TC in its compression stroke. (If the
exhaust valve of cylinder No. 1 is pushed down,
piston No. 6 is at TC in its compression stroke.)

Measurement:
1. Insert a feeler gauge between the rocker arm and
the valve stem to measure the valve clearance.

NOTE: The cylinders are positioned from No. 1 to

No. 6 in that order as viewed from the fan
side.

2. If the measurement is started from cylinder No. 1,

perform the same measurement for the valves
indicated with “{” mark in the table below.
If the measurement is started from cylinder No. 6,
perform the same measurement for the valves
indicated with “×” mark.
Cylinder No. No.1 No.2 No.3 No.4 No.5 No.6
Valve Layout I E I E I E I E I E I E
When the meas-
ure-ment is started { { { { { {
from cylinder No.1
When the meas-
ure-ment is started × × × × × ×
from cylinder No.6

3. Rotate the crank shaft 360 degrees.

Align the TC mark with the pointer. Then, move
on to the next valve to be measured and perform
the measurement. Repeat the measurement for
the other valves.

T4-3-4
 OPERATIONAL PERFORMANCE TEST / Engine Test
Evaluation:
Standard Valve Clearance (Cold Engine):
• Intake valve: 0.40 mm (0.016 in)
• Exhaust valve: 0.40 mm (0.016 in)

Adjustment:
If the measured valve clearances do not conform to
the standard value, adjust the valve clearance in the
same order of the measurement.

1. Completely loosen the adjusting screws on the

bridge and rocker arm. Insert a 0.4 mm feeler
gauge. Adjust the valve clearance with the ad-
justing screw on the rocker arm. Do not adjust the Feeler Gauge (0.4 mm)
clearance too tight at this stage. Leave a slight Rocker Arm
looseness. Securely lock the adjusting screw with
Adjusting Screw
the lock nut. and Lock Nut
2. With the feeler gauge inserted, turn the adjusting
screw until the screw head comes into contact
with the valve head. Confirm that the feeler gauge
can be removed and inserted smoothly but with
Adjusting
some tightness. Securely lock the adjusting screw Screw and
with the lock nut. Lock Nut
3. Loosen the adjusting screw located on the other Bridge
side of the bridge. Insert the feeler gauge and
adjust the clearance. Securely lock the adjusting
screw with the lock nut.

T111-06-02-009

T4-3-5
 OPERATIONAL PERFORMANCE TEST / Engine Test
NOZZLE CHECK
Summary
1. Check the injection pressure and the spray pat-
tern with a nozzle tester.
2. Before starting work, clean the nozzle holder
mounting area to avoid contaminating the engine
system.

Preparation
1. Remove the nozzle holders.
Remove all nozzle holders and fuel injection pip-
ings from the engine.
2. Attach a nozzle holder to the nozzle tester.

Measurement

CAUTION: Never touch spray directly. The T107-06-02-006

fuel spray from the nozzle may penetrate the
skin, resulting in serious injury. If fuel pene-
trates into the blood stream, it may cause
blood toxication.

1. Injection pressure
After attaching the nozzle holder to the nozzle
tester, strongly make several strokes of the tester
to inject fuel. Then, while operating the tester at
approx. 60 time strokes a minute, measure the
fuel injection pressure.
If adjustment is required, loosen the lock nuts and
adjust the adjusting screws. Turn clockwise to in-
crease the pressure, and counterclockwise to de-
crease the pressure.

2. Spray pattern
For this test, turn the pressure tester knob to by-
pass the pressure gauge. Attach the nozzle
holder to the nozzle tester. Strongly make several
strokes of the tester and check the fuel spray pat-
tern.

3. Leak condition
Be sure to keep the pressure as that just before
the injection. Then check any oil leaks around the
nozzle.

NOTE: Use clean diesel oil.

T4-3-6
 OPERATIONAL PERFORMANCE TEST / Engine Test
Evaluation Normal
1. Standard Injection Pressure:
Refer to T4-5 Operational Performance Standard
Table.

2. Spray Pattern
• Large-size spray should not be visible to the
naked eye.

• No stray sideways sprays should be seen.

• During initial injection stage, spray size should

be fine and injected intermittently. T102-02-11-005
Abnormal
• There should be no drips found.

• Injection spray angle must be normal.

3. Oil Tight Condition

• No fuel leaks.

T102-02-11-006

Adjustment
• To adjust the injection pressure, loosen the lock
nuts. Adjust the adjusting screw.
Turn clockwise to increase the pressure, and
counterclockwise to decrease the pressure.

• After adjusting, retighten the lock nuts.

T107-06-02-007

T4-3-7
 OPERATIONAL PERFORMANCE TEST / Engine Test
INJECTION TIMING
Inspection
1. Remove the flywheel timing mark cover. Align the
10° BTDC mark (before piston No.1 TDC) on the
flywheel or the crankshaft damper pulley to the
pointer, by turning the ring gear counterclockwise
(as seen from the flywheel side) using a metal
Pointer
bar.
Piston No.1 is now positioned in its compression
stroke.

2. Check alignment of the injection pump flywheel

(or the timing advancer) notched line and injec-
tion pump body notched line.
If the two notched lines are in alignment, the in-
jection timing is correct.
T16J-04-02-004

Injection Pump Flywheel

Adjustment
1. Loosen the two coupling bolts on the injection Injection Pump Pointer
pump flywheel (or the timing advancer).
Align the injection pump flywheel (or the timing
advancer) notched line and injection pump body
notched line.

2. Tighten the timing adjusting bolt to specification.

: 37 to 41 Nxm (3.8 to 4.2 kgfxm)

3. To advance the timing

Turn the injection pump flywheel (or timing ad- T16J-04-02-005
vancer) toward out while the injection pump cou-
pling bolts are loosened condition.

4. To retard the timing

Turn the injection pump flywheel (or timing ad-
vancer) toward in (cylinder block side) in the in-
jection pump coupling bolts loosened condition.

Bolt

T16J-04-02-006

T4-3-8
 OPERATIONAL PERFORMANCE TEST / Excavator Test
TRAVEL SPEED
Summary:
Measure the time required for the excavator to travel
a 20 m (65.6 ft) test track.

Preparation:
1. Adjust the track sag on both side tracks equally.
2. Prepare a flat and solid test track 20 m (65.6 ft) in
length with extra length of 3 to 5 m (9.8 to 16 ft)
Arm Rolled-In, Bucket Rolled-In
on both ends for machine acceleration and End
deceleration. Bucket Height: 0.3 to 0.5 m
3. Hold the bucket 0.3 to 0.5 m (12 to 20 in) above
the ground with the arm and bucket rolled in. Start
20 m Deceleration
4. Maintain hydraulic oil temperature at 50±5 °C Zone
(122±9 °F). 3 to 5 m
Acceleration
Measurement: Zone
3 to 5 m
1. Measure both the slow and fast speeds of the
machine. T105-06-03-001
2. Select the following switch positions:
Travel Engine Power Work Auto-Idle/
Mode Control Mode Mode Acceleration
Switch Dial Switch Switch Selector
Slow Digging
Fast Idle HP Mode OFF
Mode Mode
Fast Digging
Fast Idle HP Mode OFF
Mode Mode

1. Start traveling the machine in the acceleration

zone with the travel levers to full stroke.
2. Measure the time required to travel 20 m (65.6 ft).
3. After measuring the forward travel speed, turn the
upperstructure 180° and measure the reverse
travel speed.
4. Repeat steps 4. to 5. three times in each direction
and calculate the average values.

Evaluation:
Refer to the Performance Standard Table in Group
T4-2.

Remedy:
Refer to the Troubleshooting B in Group T5-4.

T4-4-1
 OPERATIONAL PERFORMANCE TEST / Excavator Test
TRACK REVOLUTION SPEED
Summary:
Measure the track revolution cycle time with the track
raised off ground.

Preparation:
1. Adjust the track sag of both side tracks to be
equal.
2. On the track to be measured, mark one shoe with
chalk.
3. Swing the upperstructure 90° and lower the
bucket to raise the track off ground. Keep the
boom-arm angle between 90 to 110° as shown.
Place blocks under the machine frame.
T142-05-03-011

CAUTION: Securely support the raised track

using wooden blocks.

1. Maintain the hydraulic oil temperature at 50±5 °C

(122±9 °F).

Measurement:
1. Select the following switch positions:
Travel Engine Power Work Auto-Idle/
Mode Control Mode Mode Acceleration
Switch Dial Switch Switch Selector
Slow Digging
Fast Idle HP Mode OFF
Mode Mode
Fast Digging
Fast Idle HP Mode OFF
Mode Mode
1. Operate the travel control lever of the raised track
to full stroke.
2. Measure the time required for 3 revolutions in
both directions after a constant track revolution
speed is obtained.
3. Raise the other side and repeat the above pro-
cedures.
4. Repeat steps 2. to 4. three times and calculate
the average values.
T142-05-03-012
Evaluation:
Refer to the Performance Standard Table in Group
T4-2.

NOTE: The measurement data obtained through

the raised track revolution test may have
wide variations. Therefore, the evaluation
based on the results obtained from the 20
m travel speed check described before is
more recommendable.

Remedy:
Refer to the Troubleshooting B in Group T5-4.

T4-4-2
 OPERATIONAL PERFORMANCE TEST / Excavator Test
MISTRACK CHECK
Summary:
1. Allow the machine to travel 20 m (65.6 ft). Meas-
ure the maximum tread deviation from the tread
chord line drawn between the travel start and end Maximum Distance
points to check the performance equilibrium be-
tween both sides of the travel device systems
(from the main pump to the travel motor). Acceleration
2. If measured on a concrete surface, the tread de- Zone:
viation has a trend to decrease. 3 to 5 m
20 m

Preparation:
1. Adjust the track sag of both tracks to be equal.
2. Provide a flat, solid test yard 20 m (65.6 ft) in
length, with extra length of 3 to 5 m (9.8 to 16 ft)
on both ends for machine acceleration and de- T105-06-03-022

celeration.
3. Hold the bucket 0.3 to 0.5 m (12 to 20 in) above
the ground with the arm and bucket rolled in.
4. Maintain the hydraulic oil temperature at 50±5 °C
(122±9 °F).

Measurement:
1. Measure the amount of mistracking in both fast,
and slow travel speeds.
2. Select the following switch positions:
Travel Engine Power Work Auto-Idle/
Mode Control Mode Mode Acceleration
Switch Dial Switch Switch Selector
Slow Digging
Fast Idle HP Mode OFF
Mode Mode
Fast Digging
Fast Idle HP Mode OFF
Mode Mode

1. Start traveling the machine in the acceleration

zone with the travel levers at full stroke.
2. Measure the maximum distance between a
straight 20 m (65.6 ft) tread chord line and the
tread made by the machine.
3. After measuring the tracking in forward travel,
turn the upperstructure 180° and measure in re-
verse travel.
4. Repeat steps 3. to 5. three times and calculate
the average values.

Evaluation:
Refer to the Performance Standard Table in Group
T4-2.

Remedy:
Refer to the Troubleshooting B in Group T5-4.

T4-4-3
 OPERATIONAL PERFORMANCE TEST / Excavator Test
TRAVEL MOTOR LEAKAGE

Summary:
To measure the parking brake function on a specified
slope.

Preparation:
1. The surface of the test slope shall be even with a 0.2 to 0.3 m
gradient of 20 % (11.31°).
2. Hold the bucket 0.2 to 0.3 m (8 to 12 in) above
the ground with the arm and bucket fully rolled in.
3. Maintain the hydraulic oil temperature at 50±5 °C
(122±9 °F). T105-06-03-004

Measurement:
1. Select the following switch positions:

Travel Mode Engine Control Power Mode Work Mode Auto-Idle Switch/
Switch Dial Switch Switch Auto-Acceleration Selector
Fast Speed
Fast Idle HP Mode Digging Mode OFF
Mode

1. Measure the travel parking brake slip amount

while parked.
1-1. Climb the slope and place the travel levers in
neutral.
1-2. Stop the engine.
1-3. After the machine stops, put alignment marks
on a track link or shoe, and the track side
frame.
1-4. After 5 minutes, measure the distance between
the marks on the track link or shoe and the
track side frame. Alignment marks on the track side frame
and shoe when the machine comes to a stop.
Evaluation: Displacement measured after 5 minutes.
Refer to the Performance Standard Table in Group
T105-06-03-006
T4-2.

T4-4-4
 OPERATIONAL PERFORMANCE TEST / Excavator Test
SWING SPEED
Summary:
Measure the time required to swing three complete
turns.

Preparation:
1. Check the lubrication of the swing gear and swing
bearing.
2. Place the machine on flat, solid ground with am-
ple space for swinging. Do not conduct this test T145-05-03-007

on slopes.
3. With the bucket empty, position the front attach-
ment as follows:
Backhoe:
With the arm cylinder fully retracted, and the
bucket cylinder fully extended, raise the boom so
that the arm tip pin height is flush with the boom
foot pin height.
Loading Shovel:
With the arm cylinder and the bucket cylinder fully
extended, raise the boom so that the arm tip pin T145-05-03-008

height is flush with the boom foot pin height.

4. Maintain the hydraulic oil temperature at 50±5 °C
(122±9 °F).
CAUTION: Prevent personal injury. Always
make sure that the area is clear and that
co-workers are out of the swing area before
starting the measurement.

Measurement:
1. Select the following switch positions:

Engine Control Power Mode Work Mode Auto-Idle Switch/

Dial Switch Switch Auto-Acceleration Selector
Fast Idle HP Mode Digging Mode OFF

1. Operate swing control lever fully.

2. Measure the time required to swing 3 turns in one
direction.
3. Operate swing control lever fully in the opposite
direction and measure the time required for 3
turns.
4. Repeat steps (2 to 4) three times and calculate
the average values.

Evaluation:
Refer to the Performance Standard Table in Group
T4-2.

Remedy:
Refer to the Troubleshooting B in Group T5-4.

T4-4-5
 OPERATIONAL PERFORMANCE TEST / Excavator Test
SWING FUNCTION DRIFT CHECK
Summary:
Measure the swing drift on the bearing outer circum-
ference when stopping after a 180° full-speed swing.

Preparation:
1. Check the lubrication of the swing gear and swing
bearing.
2. Place the machine on flat, solid ground with am-
ple space for swinging. Do not conduct this test
on a slope.
Two Check Marks
3. With the bucket empty, position the front attach-
ment as follows: T105-06-03-008

Backhoe:
With the arm cylinder fully retracted, and the
bucket cylinder fully extended, raise the boom so
that the arm tip pin height is fluch with the boom
foot pin height.
Loading shovel:
With the arm cylinder and the bucket cylinder fully
extended, raise the boom so that the arm tip pin
height is flush with the boom foot pin height.
4. Make two chalk marks: one on the swing bearing
and one directly below it on the track frame.
5. Swing the upperstructure 180°. T105-06-03-009

6. Maintain the hydraulic oil temperature at 50±5 °C

(122±9 °F).
Measure Difference Between Marks
CAUTION: Prevent personal injury. Always
make sure that the area is clear and that
co-workers are out of the swing area before
starting the measurement.

Measurement:
Marking on the Track Frame
1. Select the following switch positions:
Auto-Idle/ Marking on the Swing Bearing
Engine Con- Power Mode Work Mode
Acceleration
trol Dial Switch Switch
Selector T105-06-03-010
Digging
Fast Idle HP Mode OFF
Mode
1. Operate the swing control lever fully and return it
to the neutral position when the mark on the up-
perstructure aligns with that on the track frame
after swinging 180° .
2. Measure the distance between the two marks.
3. Align the marks again, swing 180°, then test in
the opposite direction.
4. Repeat steps 3. to 5. three times each and cal-
culate the average values.

Evaluation:
Refer to the Performance Standard Table in Group
T4-2.
Remedy:
Refer to the Troubleshooting B in Group T5-4.

T4-4-6
 OPERATIONAL PERFORMANCE TEST / Excavator Test
SWING MOTOR LEAKAGE
Summary:
Check for upperstructure drift while suspending a
load on a slope.

Preparation:
1. Check the lubrication of the swing gear and swing
bearing.
2. Load bucket fully. In lieu of loading the bucket,
weight (W) of the following specification can be
used.
Backhoe: W=2850 kg (6280 lb)
Loading shovel: W=3900 kg (8600 lb)
3. Position the front attachment as follows:
Backhoe: T105-06-03-011
With the arm cylinder fully retracted, and the
bucket cylinder fully extended, raise the boom so
that the arm tip pin height is flush with the boom
foot pin height.
Loading shovel:
With the arm cylinder and the bucket cylinder fully
extended, raise the boom so that the arm tip pin
height is flush with the boom foot pin height.
4. Park the machine on a smooth slope with a gra-
dient of 26.8% (15°).
5. Swing the upperstructure to position it 90° to the
slope. Make aligning marks on the swing bearing Measure Difference Between Marks
periphery and track frame using tape, as illus-
trated.
6. Maintain the hydraulic oil temperature at 50±5 °C
(122±9 °F).

Measurement: Marking on the Track Frame

1. Select the following switch position:
Auto-Idle/ Marking on the Swing Bearing
Power Mode Work Mode
Acceleration
Switch Switch
Selector T105-06-03-010

HP Mode Digging Mode OFF

1. Maintain the engine at slow idle. After five min-

utes, measure the difference between the marks
along the swing bearing periphery and the track
frame.
2. Perform the measurement in both right and left
swing directions.
3. Perform the measurement three times in each
direction and calculate the average values.

Evaluation:
Refer to the Performance Standard Table in Group
T4-2.

Remedy:
Refer to the Troubleshooting B in Group T5-4.

T4-4-7
 OPERATIONAL PERFORMANCE TEST / Excavator Test
MAXIMUM SWINGABLE SLANT ANGLE
Summary:
With the upperstructure swung 90° to the slope,
check the maximum slant angle on which the upper-
structure can swing to the uphill side.

Preparation:
1. Check that the swing gear and bearing are well
lubricated.
2. Load bucket fully. In lieu of loading the bucket,
weight (W) of the following specification can be
used.
Backhoe: W=2850 kg (6280 lb)
Loading shovel: W=3900 kg (8600 lb)
3. Position the front attachment as follows:
Backhoe: T105-06-03-011
With the arm cylinder fully retracted and the
bucket cylinders fully extended .
Loading shovel:
With the arm cylinder fully extended and the
bucket cylinders fully extended. Hold the arm tip
pin to the position flush with the boom foot pin
height.
4. Climb a slope and swing the upperstructure 90°
to the slope.
5. Maintain the hydraulic oil temperature at 50±5 °C
(122±9 °F).

Measurement:
1. Select the following switch positions:
Engine Auto-Idle/
Power Mode Work Mode
Control Acceleration
Switch Switch
Dial Selector
Fast Idle HP Mode Digging Mode OFF

1. Operate the swing lever to full stroke to swing the

upperstructure to the uphill side.
2. If the machine can swing, measure the cab floor
slant angle.
3. Increase the slope angle and repeat steps 2. and
3. Check both clockwise and counterclockwise.
4. Perform the measurement three times.

Evaluation:
Refer to the Performance Standard Table in Group
T4-2.

Remedy:
Refer to the Troubleshooting B in Group T5-4.

T4-4-8
 OPERATIONAL PERFORMANCE TEST / Excavator Test
SWING BEARING PLAY
Summary:
Measure the swing bearing play using a dial gauge to
check the wear of bearing races and balls.

Preparation:
1. Check swing bearing mounting bolts for loose-
ness.
2. Check the lubrication of the swing bearing. Con-
firm that bearing rotation is smooth and without
noise.
3. Install a dial gauge on the track frame as shown,
Magnetic Base Dial Gauge
using a magnetic base.
T105-06-03-014
4. Position the upperstructure so that the boom
aligns with the tracks facing towards the front
idlers.
5. Position the dial gauge so that its needle point
comes into contact with the bottom face of the
bearing outer race.
6. Bucket should be empty.

Round trunk
NOTE: The measured value will vary depending
on where the magnet base is secured.
Secure the magnet base onto the round
trunk or in a position as close to the round
trunk as possible.
T105-06-03-015

T4-4-9
 OPERATIONAL PERFORMANCE TEST / Excavator Test
Measurement:
1. Position the front attachment as follows:
Backhoe:
With the arm cylinders fully retracted and the
bucket cylinders fully extended, position the arm
tip pin height is flush with the boom foot pin height.
Loading shovel:
With the arm cylinder fully extended and the
bucket cylinders fully extended, position the arm
top pin height is flush with the boom foot pin
height.
2. Lower the bucket to the ground and use it to raise
the front idler 0.5 m (20 in). Record the dial gauge
reading (h2).
3. Calculate bearing play (H) from this data (h1 and
h2) as follows:
H=h2−h1

Evaluation:
Refer to the Performance Standard Table in Group
T4-2.

Backhoe Front
Measurement : (h1) Measurement : (h2)

Figure 1 Figure 2
T142-05-03-006

Loading Shovel Front

Measurement : (h1) Measurement : (h2)

Figure 1 Figure 2
T142-05-03-005

T4-4-10
 OPERATIONAL PERFORMANCE TEST / Excavator Test
HYDRAULIC CYLINDER CYCLE TIME
Summary:
Check the overall operational performance of the
front attachment hydraulic system (between the hy-
draulic pumps and each cylinder) by measuring the
cycle time of the boom, arm, bucket, and bucket
dump (open/close) cylinders with the empty bucket.

Preparation:
1. Maintain the hydraulic oil temperature at 50±5 °C
(122±9°F).

Measurement:
1. Select the following switch positions:
Engine Auto-Idle/
Power Mode Work Mode
Control Acceleration
Switch Switch Backhoe
Dial Selector
Fast Idle HP Mode Digging Mode OFF

1. Position the front attachment as described in the Boom Cylinder

following. Then, measure the operating time until
the cylinder reaches the stroke end by fully mov-
ing the control lever.
• Backhoe
Boom Cylinder: T145-05-03-012
With the bucket cylinder fully extended and the
arm cylinder fully retracted, lower the bucket to
the ground.
Arm Cylinder:
Adjust the boom cylinder stroke so that the
bucket bottom height is 0.5 m (20 in) above the Arm Cylinder
ground with the bucket cylinder fully extended
while positioning the center line between the arm
and bucket connection pin centers vertical with
T145-05-03-013
the arm cylinder extended half stroke.
Bucket Cylinder:
Adjust the boom and arm cylinder so that the
center of full stroke movement of the bucket is
positioned vertically.

Bucket Cylinder

T145-05-03-014

T4-4-11
 OPERATIONAL PERFORMANCE TEST / Excavator Test
• Loading Shovel
Loading Shovel
Boom Cylinder:
With the bucket cylinder and the arm cylinder fully
extended, lower the bucket to the ground.
Arm Cylinder: Boom Cylinder
With the arm fully retracted, position the bucket
so that the rear bucket does not come in contact
with the arm stopper. Then, adjust the boom cyl-
inder stroke to position the bucket bottom 1 m (39
in) above the ground. T145-05-03-015
Bucket Cylinder:
With the bucket closed and held in a load dump
position, adjust the boom cylinder stroke so that
bucket bottom height is approx. 1 m (39 in) above
the ground.
Bucket Open-Close Cylinder:
With the bucket cylinder and arm cylinder fully Arm Cylinder
extended, adjust the boom cylinder stroke so that T145-05-03-016
the bucket bottom height approx. 1 m (39 in)
above the ground.
1. Repeat the measurement three times and calcu-
late the average values.

Evaluation:
Refer to T4-2 Operational Performance Standard. Bucket Cylinder

T145-05-03-017
Remedy:
Refer to the T-5-4 Troubleshooting B.

Dump Cylinder

T145-05-03-018

T4-4-12
 OPERATIONAL PERFORMANCE TEST / Excavator Test
DIG FUNCTION DRIFT CHECK
Summary:
Measure dig function drift, which can be caused by
oil leakage in the control valve and boom, arm, and
bucket cylinders, with the loaded bucket.

NOTE: When testing the dig function drift just after

cylinder replacement, slowly operate each
cylinder to its stroke end to release air.
T145-05-03-020

Preparation:
1. Load bucket fully. In lieu of loading the bucket,
weight (W) of the following specification can be
used.
Backhoe: W=2850 kg (6280 lb)
Loading Shovel: W=3900 kg (8600 lb)
2. Position the front attachment as follows:
Backhoe:
With the arm cylinder fully retracted and the
T145-05-03-021
bucket cylinder fully extended.
Loading shovel:
With the arm cylinder and the bucket cylinder fully Boom and Bucket Cylinder Retraction
extended.
Raise the boom so that the arm tip pin height is Mark Mark
flush with the boom foot pin height concerning
backhoe and loading shovel.
3. With the arm rolled out and the bucket rolled in,
hold the bucket so that the height of the bucket
pin is the same as the boom foot pin.
4. Maintain the hydraulic oil temperature at 50±5 °C
(122±9 °F). T110-06-03-002

Measurement: Arm Cylinder Extension

1. Stop the engine.
2. Five minutes after the engine has been stopped,
measure the change in the position of the bottom
of the bucket, as well as the boom, arm and
bucket cylinders. Mark
3. Repeat step 2. three times and calculate the av-
erage values.

Evaluation:
Refer to the Performance Standard Table in Group
T4-2.
T110-06-03-001
Remedy:
Refer to the Troubleshooting B in Group T5-4.

T4-4-13
 OPERATIONAL PERFORMANCE TEST / Excavator Test
CONTROL LEVER OPERATING FORCE

Summary:
Use a spring scale to measure the maximum resis-
tance of each control lever at the middle of the grip.

Preparation:
Maintain the hydraulic oil temperature at 50±5 °C
(122±9 °F).

Measurement:
1. Start the engine.
2. Select the following switch positions:
Engine Auto-Idle/
Power Mode Work Mode
Control Acceleration
Switch Switch T107-06-03-003
Dial Selector
Fast Idle HP Mode Digging Mode OFF

CAUTION: Prevent personal injury. Always

make sure that the area is clear and that
co-workers are out of the swing area before
starting the measurement.
1. Operate each boom (raise) arm and bucket lever
to the fully and measure the maximum operating
force for each with each actuator relieved.
2. Operate boom (lower) lever and measure the
maximum operating force with the boom lower re-
lieved by jacking up the machine in a safe area.
3. Operate swing lever and measure the maximum
operating force with swing relieved after securing T107-06-03-004
the front attachment to prevent swinging.
4. Lower the bucket to the ground to raise one track
off the ground. Operate the travel lever to full
stroke and measure the maximum operating
force required. When finished, lower the track
and then jack-up the other track.
5. Repeat steps 3. to 4. three times and calculate
the average values.

Evaluation:
Refer to the Performance Standard Table in Group
T4-2.

T4-4-14
 OPERATIONAL PERFORMANCE TEST / Excavator Test
CONTROL LEVER STROKE
Summary:
1. Measure each lever stroke at the lever top using
a ruler.
2. Measure the lever stroke at the grip center of
each control lever.
3. In case lever stroke play is present in the neutral
position, add half (1/2) the play present to both
side lever strokes.

NOTE: When the lever has play, take a half of this

value and add it to the measured stroke.

Preparation:
Maintain the hydraulic oil temperature at 50±5 °C T107-06-03-005

(122±9 °F).

Measurement:
1. Stop the engine.
2. Measure each lever stroke at the lever top from
neutral to the stroke end using a ruler.
3. Repeat step (2) three times and calculate the av-
erage values.

Evaluation:
Refer to the Performance Standard Table in Group
T4-2.

T4-4-15
 OPERATIONAL PERFORMANCE TEST / Excavator Test
BOOM RAISE/SWING COMBINED OP-
ERATION CHECK
Summary:
Check boom raise and swing movement speeds
while operating both functions simultaneously.

Preparation:
1. Start the engine and run it at fast idle. Operate the
boom raise function and check to be sure that the T142-05-03-007

cylinder movement is smooth, with out sticking.

2. Position the machine with front attachment posi-
tioned as illustrated and with the bucket empty.
3. Maintain the hydraulic oil temperature at 50 ± 5
°C (122±9 °F).

CAUTION: Prevent personal injury. Always

T142-05-03-008
make sure that the area is clear and that co-
workers are out of the swing area before
starting the measurement.

Measurement:
1. Select the following switch positions:
Engine Auto-Idle/
Power Mode Work Mode
Control Acceleration
Switch Switch
Dial Selector
Fast Idle HP Mode Digging Mode OFF

2. Raise the boom and swing simultaneously.

3. When the upperstructure rotates 90°, release the
control levers to stop both functions. Measure the T107-06-03-010

time required to swing 90° and the height (H) of

the bucket teeth.
4. Repeat the steps (2 to 3) three times and calcu-
late the average values.

Evaluation:
Refer to the performance Standard Table in Group
T4-2.
H

Remedy:
Refer to the Troubleshooting B in Group T5-4.

T107-06-03-011

T4-4-16
 OPERATIONAL PERFORMANCE TEST / Component Test
PRIMARY PILOT PRESSURE
Preparation:
1. Shut down the engine properly.

CAUTION: The hydraulic oil tank cap may fly

off if turned quickly. Slowly turn it to release
internal pressure before removing it.

2. Move all control levers to release pressure re-

maining in the system. Slowly turn the hydraulic
oil tank cap approximately 30 degrees
counter-clockwise to release internal pressure
from the hydraulic oil tank.

: 4 mm
T111-06-04-001

3. Disconnect the hose end from the pilot filter outlet

port. Install adapter (ST 6477), fitting (ST 6069),
pressure gauge (ST 6315) and coupling (ST
6332).

: 24 mm, 27 mm

1. Start the engine. Confirm that no oil leakage is

observed at the pressure gauge connection.
2. Maintain the hydraulic oil temperature at 50±5 °C
(122±9 °F).

Measurement:
1. Select the following switch positions:

Auto-Idle/
Engine Control Power Mode Work Mode
Acceleration
Dial Switch Switch
Selector
Fast Idle HP Mode Digging Mode OFF
Slow Idle HP Mode Digging Mode OFF

2. Measure the pilot pressure in specified setting

above.
3. Repeat the measurement three times and calcu-
late the average values.

Evaluation:
Refer to the Performance Standard Table in Group
T4-2.

T4-5-1
 OPERATIONAL PERFORMANCE TEST / Component Test
Primary Pilot Pressure Adjustment Procedure

Adjustment:
Adjust the setting pressure of the pilot relief valve
(the primary pilot pressure).

: 22 mm

Pilot Relief
Valve

T16J-04-04-001

1. Remove plug (1).

1
2
2. Install the estimated necessary numbers of shims
(2).

3. Tighten plug (1).

: 29.5 Nxm (3 kgfxm, 42 lbfxft)

4. Check the relief pressure of the relief valve.

NOTE: Reference : Standard Change in Pressure

Shim Thickness Change in Pressure
(mm) kPa
2
(kgf/cm ) (psi)
0.25 78 0.8 11
0.5 147 1.5 21
1.0 294 3.0 42 T111-06-04-004

T4-5-2
 OPERATIONAL PERFORMANCE TEST / Component Test
SECONDARY PILOT PRESSURE
Preparation:
1. Shut down the engine properly.
2. Press the air relief valve on top of the hydraulic oil
tank to release any remaining pressure.
3. Measure the pressure by the following methods.

NOTE: When disconnecting the pilot lines from the

signal control valve, use tool (SNAP-ON
GAN850812B:size 19.05 mm) to easily
disconnect the lines.

• Measure pressure at the location between the

pilot valve and the signal control valve:
Disconnect the pilot circuit hose to be measured
from the signal control valve. Connect hose
(7/16-20UNF approx. 400 mm long) to the sig-
nal control valve. Install tee (ST 6450) and
pressure gauge (ST 6942) between the hoses.
• Measure pressure at the location between the T157-05-04-011
control valve and the signal control valve:
Disconnect the pilot circuit line to be measured
between the signal control valve and the control
valve. Connect hose to the signal control valve.
Install tee (ST 6451) and pressure gauge (ST
6942) between the hose and the control valve.
: 14 mm, 17 mm

4. Start the engine. Confirm that no oil leakage is

observed at the pressure gauge connection.
5. Maintain the hydraulic oil temperature at 50±5 °C
(122±9 °F).

Measurement:
1. Select the following switch positions:
Auto-Idle/
Engine Power Mode Work Mode
Acceleration
Control Dial Switch Switch
Selector
Digging
Fast Idle HP Mode OFF
Mode
Digging
Slow Idle HP Mode OFF
Mode
2. Measure the pilot pressure in each specified set-
ting above with the corresponding control lever
operated full stroke.
3. Repeat the measurement three times and calcu-
late the average values.

Evaluation:
Refer to the Performance Standard Table in Group
T4-2.

Remedy:
Refer to the Troubleshooting B in Group T5-4.

T4-5-3
 OPERATIONAL PERFORMANCE TEST / Component Test
MAIN RELIEF PRESSURE SHIFT CON-
TROL PRESSURE (SA Pressure)
The control pressure can also be measured with Dr.
EX.

Preparation:
1. Shut down the engine properly.

CAUTION: The hydraulic oil tank cap may fly

off if turned quickly. Slowly turn it to release
internal pressure before removing it.
2. Move all control levers to release pressure re-
maining in the system. Slowly turn the hydraulic
oil tank cap approximately 30 degrees
counter-clockwise to release internal pressure SA
from the hydraulic oil tank.
: 4 mm

3. Disconnect the hose end from the solenoid valve

T16J-04-04-001
SA output port. Install adapter (ST 6451), fitting
(ST 6069), pressure gauge (ST 6315) and cou-
pling (ST 6332).
: 17 mm, 19 mm, 22 mm

4. Start the engine. Confirm that no oil leakage is

observed at the pressure gauge connection.

5. Maintain the hydraulic oil temperature at 50±5 °C

(122±9 °F).

Measurement:
1. Select the following switch and lever positions:

Auto-Idle /
Engine Con- Control Power Mode Auto-Accel- Work Mode Power Digging
trol Dial Levers Switch eration Switch Switch
Selector
Travel lever Digging
Fast Idle HP Mode OFF OFF
operation Mode
Fast Idle All in neutral HP Mode OFF Precision OFF
Digging
Fast Idle All in neutral HP Mode OFF *ON
Mode
Digging
Fast Idle All in neutral HP Mode OFF OFF
Mode

NOTE: *The power boost functions only for 8 sec- Remedy:

onds. Refer to the troubleshooting B in Group T5-4.

2. Read the pressure gauge in each setting above.

3. Repeat the measurement three times and calcu-

late the average values.

Evaluation:
Refer to the performance standard table in Group
T4-2.

T4-5-4
 OPERATIONAL PERFORMANCE TEST / Component Test
TRAVEL MODE SHIFT CONTROL PRES-
SURE (SB Pressure)
The control pressure can also be measured with Dr.
EX.

Preparation:
1. Shut down the engine properly.

CAUTION: The hydraulic oil tank cap may fly

off if turned quickly. Slowly turn it to release
internal pressure before removing it.
SB
2. Move all control levers to release pressure re-
maining in the system. Slowly turn the hydraulic
oil tank cap approximately 30 degrees
counter-clockwise to release internal pressure
from the hydraulic oil tank.
T16J-04-04-001

: 4 mm

3. Disconnect the hose end from the solenoid valve

SB output port. Install adapter (ST 6451), fitting
(ST 6069), pressure gauge (ST 6315) and cou-
pling (ST 6332).

: 17 mm, 19 mm, 22 mm

1. Start the engine. Confirm that no oil leakage is

observed at the pressure gauge connection.

1. Maintain the hydraulic oil temperature at 50±5 °C

(122±9 °F).

Measurement:
1. Select the following switch positions:
Auto-Idle /
Engine Travel Mode Power Mode Work Mode
Acceleration
Control Dial Switch Switch Switch
Selector
Digging
Fast Idle Fast Speed HP Mode OFF
Mode
Digging
Slow Idle Slow Speed HP Mode OFF
Mode

2. Read the pressure gauge in each setting above.

3. Repeat the measurement three times and calcu-

late the average values.

Evaluation:
Refer to the performance standard table in Group
T4-2.

Remedy:
Refer to the troubleshooting B in Group T5-4.

T4-5-5
 OPERATIONAL PERFORMANCE TEST / Component Test
BOOM MODE SELECTOR CONTROL
PRESSURE (SC Pressure)
The control pressure can also be measured with Dr.
EX.

Preparation:
1. Shut down the engine properly. SC

CAUTION: The hydraulic oil tank cap may fly

off if turned quickly. Slowly turn it to release
internal pressure before removing it.

2. Move all control levers to release pressure re-

maining in the system. Slowly turn the hydraulic
oil tank cap approximately 30 degrees
counter-clockwise to release remaining pressure
from the hydraulic oil tank.

: 4 mm

3. Disconnect the hose end from the solenoid valve T16J-04-04-001

SC output port. Install adapter (ST 6451), fitting

(ST 6069), pressure gauge (ST 6315) and cou-
pling (ST 6332).

: 17 mm, 19 mm, 22 mm

1. Start the engine. Confirm that no oil leakage is

observed at the pressure gauge connection.

1. Maintain the hydraulic oil temperature at 50±5 °C

(122±9 °F).

Measurement:
1. Select the following switch and lever positions:
Auto-Idle /
Engine Power Mode Work Mode Boom Mode
Acceleration
Control Dial Switch Switch Selector Switch
Selector
Digging
Fast Idle HP Mode OFF ON
Mode
Digging
Slow Idle HP Mode OFF OFF
Mode

2. Read the pressure gauge in each setting above.

3. Repeat the measurement three times and calcu-

late the average values.

Evaluation:
Refer to the performance standard table in Group
T4-2.

Remedy:
Refer to the troubleshooting B in Group T5-4.

T4-5-6
 OPERATIONAL PERFORMANCE TEST / Component Test
MAIN PUMP DELIVERY PRESSURE
The main pump delivery pressure can also be meas-
ured with the built-in diagnosing system or Dr.EX.

Preparation:
1. Shut down the engine properly.
2. Press the air relief valve on top of the hydraulic oil
tank to release any remaining pressure.
Main Pump Delivery Port
3. Remove the plug from the main pump delivery (5-Spool Side)
port. Install adapter (ST 6069) and pressure
gauge (ST 6934) on the port.

: 6 mm

Or connect Dr.EX to the machine for main pump

delivery pressure monitoring.
1. Start the engine. Confirm that no oil leakage is
observed at the pressure gauge connection.
2. Maintain the hydraulic oil temperature at 50±5 °C
(122±9 °F).

Measurement: Main Pump Delivery Port

1. Select the following switch positions: (4-Spool Side)
Auto-Idle / T16J-04-04-004
Engine Power Mode Work Mode
Acceleration
Control Dial Switch Switch
Selector
Digging
Fast Idle HP Mode OFF
Mode

2. Measure the pressure with the control levers in

neutral.
3. Repeat the measurement three times and calcu-
late the average values.

Evaluation:
Refer to the Performance Standard Table in Group
T4-2.

Remedy:
Refer to the Troubleshooting B in Group T5-4.

T4-5-7
 OPERATIONAL PERFORMANCE TEST / Component Test
MAIN RELIEF PRESSURE
Measure the main relief valve setting pressure at the
main pump delivery port.
The main relief pressure can also be measured with
the built-in diagnosing system or Dr.EX.

Summary:
Measure the main relief valve setting pressure at the
main pump delivery port.

Preparation:
1. Shut down the engine properly.
Main Pump Delivery Port
2. Press the air relief valve on top of the hydraulic oil (5-Spool Side)
tank to release any remaining pressure.
3. Remove the plug from the main pump delivery
port. Install adapter (ST 6069) and pressure
gauge (ST 6934) on the port.

: 6 mm

Or connect Dr.EX to monitor the main pump de-

livery pressure.
1. Start the engine. Confirm that no oil leakage is
observed at the pressure gauge connection.
2. Maintain the hydraulic oil temperature at 50±5 °C
(122±9 °F). Main Pump Delivery Port
(4-Spool Side)
Measurement: T16J-04-04-004

1. Select the following switch positions:

Auto-Idle /
Engine Power Mode Work Mode
Acceleration
Control Dial Switch Switch
Selector
Digging
Fast Idle HP Mode OFF
Mode

2. Relieve each actuator to measure the main relief

pressures.
First, slowly operate bucket, arm, and boom con-
trol levers to the stroke end to relieve each func-
tion.
3. As for the swing function, secure the up-
per-structure immovable. Slowly operate the
swing lever to relieve the swing function.
4. As for the travel function, secure the tracks
against an immovable object. Slowly operate the
travel levers to relieve the travel function.
5. While the power digging switch is pushed, slowly
operate bucket, arm and boom control levers to
the stroke end to relieve each function. (Measure
within 8 seconds.)

Evaluation:
Refer to the Performance Standard Table in Group
T4-2.

T4-5-8
 OPERATIONAL PERFORMANCE TEST / Component Test

NOTE: In case pressures of all circuits are low, the

pressure of the main relief valve may de-
crease. In case pressures of specified cir-
cuits are low, pressures of some other
parts except the main relief valve may de-
crease.

• Main Relief Valve Setting Adjustment procedure

When adjusting the increased pressure (when
travel or power digging switch is ON), adjust the
higher main relief pressure.
When adjusting the normal main relief pressure,
adjust the lower main relief pressure.
When adjusting the higher main relief pressure,
the lower main relief pressure setting is changed
accordingly. Therefore, be sure to adjust the
lower main relief pressure after adjusting the
higher main relief pressure. Front

• High-Side Relief Setting Adjustment Procedure.

Main Relief Valve

1. Loosen nut (2). T16J-03-03-002

Lightly tighten plug (1) until the end of plug (1) 1

comes into contact with sleeve A. 2
Tighten lock nut (2).
: 30 mm 3
Lock Nut (2) :Less then 59 N⋅m (6 kgf⋅m) 4

2. Loosen lock nut (4). 5 A

Turn Plug (3) clockwise to adjust the relief pres-
sure setting referring to the table below.

: 41 mm
Lock Nut (4) :Less then 98 N⋅m (10 kgf⋅m)

• Low-Side Relief Setting Adjustment Procedure.

3. Loosen lock nut (2).

Turn plug (1) counter clockwise to adjust the relief
pressure setting referring to the table below.
Tighten lock nut (2).
T16J-04-04-003

: 30 mm
Lock Nut (2) :Less then 59 N⋅m (6 kgf⋅m)
Plug (3, 1)
1. Check the set pressure again.

2
NOTE: Approx. 4.4 MPa (45 kgf/cm )
increase/decreases at a quarter turning.
Pressure Pressure
Increase Decrease

W107-02-05-127

T4-5-9
 OPERATIONAL PERFORMANCE TEST / Component Test
Swing Relief Valve Set-Pressure Adjustment Pro-
cedure

Adjust pressure by changing the number of shims

(2).

1. Remove the swing relief valve.

: 41 mm
Swing Relief Valve

2. Remove plug (5), sleeve (4), and piston (3).

: 30 mm

1. Adjust the set-pressure by installing shims (2)

between piston (3) and spring seat (1).

2. After adjusting, install piston (3), sleeve (4), and

plug (5).
: 118 N⋅m (12 kgf⋅m, 88 lbf⋅ft)

NOTE: Replace seals (A, B, and C) with new ones.

A: JIS B 2401 G30 1B
B: AS568-023 (Aero-Space Standard) T178-03-02-001
C: AS568-125 (Aero-Space Standard)
1 2 3 4 5
1. Install the swing relief valve.
: 176 N⋅m (18 kgf⋅m, 130 lbf⋅ft)

1. Check the set-pressure.

NOTE: Standard Change in Pressure (Reference)

Shim Thickness Change in Relief Pressure
(mm) kPa (kgf/cm 2) (psi)
A B C T178-03-02-005

0.1 610 6.3 (60)

T4-5-10
 OPERATIONL PERFORMANCE TEST / Component Test
Travel Relief Pressure Setting Adjustment
Procedure

Adjustment:
Adjust the pressure setting of the travel relief valve
using the adjusting screw after loosening the lock
nut.

1. Loosen the lock nut.

: 19 mm
Travel Relief
2. Turn the adjusting screw to adjust the pressure Valve
setting, referring to the table below.
T183-01-02-012

: 6 mm
Lock Nut
3. Retighten the lock nut.

: 19 mm

: 34.3 to 44.1 Nxm (3.5 to 4.5 kgfxm)

1. Recheck the set pressure.

Adjusting Screw

T142-05-04-007

Reference : Change in Pressure Setting

Screw Turns 1/4 1/2 3/4 1 Lock Nut
MPa 1.96 3.92 5.88 7.85 Adjusting Screw
Change in 2
Pressure (kgf/cm ) (20) (40) (60) (80)
(psi) (280) (570) (850) (1140)

Pressure Increase Pressure Decrease

W107-02-05-129

T4-5-11
 OPERATIONL PERFORMANCE TEST / Component Test
OVERLOAD RELIEF VALVE SET
PRESSURE
Summary:
1. The circuit pressure must be increased by 1. Start the engine. Confirm that no oil leakage is
applying an external force while blocking the observed at the pressure gauge connection.
return circuit from the control valve. This 2. Maintain the hydraulic oil temperature at 50±5 °C
measuring method is hazardous and the results (122±9 °F).
obtained with this method are unreliable.
2. The oil flow rate used to set the overload relief Measurement:
pressure is far less than that used to set the main 1. Select the following switch positions:
relief pressure. Therefore, measuring the over- Auto-Idle /
Engine Power Mode Work Mode
load pressure in the main circuit by increasing the Acceleration
Control Dial Switch Switch
main relief set-pressure more than the overload Selector
valve set-pressure is not a proper method. In ad- Digging
dition, in case a main relief valve designed to leak Fast Idle HP Mode OFF
Mode
a small quantity of oil before reliving is used, its
pre-leaking start pressure must be increased 2. Slowly operate bucket, arm, and boom control
more than the overload relief valve set-pressure. levers to the stroke ends to relieve each function
However, the pre-leaking start pressure is not al- one at a time.
ways increased more than the overload relief 3. Read the pressures on the pressure gauge while
valve set-pressure as the adjustable upper limit of releasing the front functions.
the main relief valve set-pressure is provided. 4. Perform the measurement for the bucket, arm,
Accordingly, the overload relief valve assembly and boom, in that order.
should be removed from the machine and 5. Repeat the measurement three times and
checked on a specified test stand at a correct oil calculate the average value for each front
flow rate. Some overload relief valves come in function.
contact with the control valve body to block the oil
passage. When this type of overload relief valve Evaluation:
is checked, the control valve body must be pre- Performance of the overload relief valves are normal
cisely finished as the test unit. Provide one con- if the measured main relief pressures are within the
trol valve other than that on the machine as a test specified value range.
kit.
3. If the overload relief valve performance must be Refer to the Performance Standard Table in Group
checked on the machine, however, measure the T4-2.
main relief pressure while releasing each front
function respective to the measuring overload
relief valve. And, assume that the overload relief
valve is functioning correctly if the obtained main
relief pressure is within the specified value range.
Measure the main pressure of the front functions Main Pump Delivery Port
as follows: (5-Spool Side)

Preparation:
1. Shut down the engine properly.
2. Press the air relief valve on top of the hydraulic oil
tank to release any remaining pressure.
3. Remove the plug from the main pump delivery
port. Install adapter (ST 6069) and pressure
gauge (ST 6934) on the port.
: 6 mm

Or connect Dr.EX to the machine for main pump Main Pump Delivery Port
delivery pressure monitoring. (4-Spool Side)
T16J-04-04-004

T4-5-12
 OPERATIONL PERFORMANCE TEST / Component Test
Overload Relief Valve Set Pressure Adjusting
Procedure

NOTE: In principle, adjust the overload relief valve

set pressure on a test stand.

Adjustment:
Adjust the pressure setting of the overload relief
valve using adjusting screw (2) after loosening lock
nut (1). Adjusting Screw

Lock Nut
1. Loosen the lock nut.
: 19 mm

2. Turn the adjusting screw to adjust the pressure

setting referring to the table below.
: 6 mm

1. Retighten the lock nut.

: 19 mm
T162-04-04-004
: 98 N⋅m (10 kgf⋅m)

1. Recheck the set pressures.

Adjusting Screw

NOTE: Standard Change in Pressure (Reference)

Screw Turns 1/4 1/2 3/4 1
Change in MPa 3.9 7.8 11.7 15.6
2
Relief (kgf/cm ) (4.0) (8.0) (120) (160)
Pressure (psi) (569) (1138) (1706) (2275) Pressure Increase Pressure Decrease

W107-02-05-129

T4-5-13
 OPERATIONL PERFORMANCE TEST / Component Test
MAIN PUMP FLOW RATE MEASUREMENT
• P-Q Control (Torque Control) 10. Connect on engine tachometer to the injection
Summary: pipe. Fully open the loading valve located on the
Main pump performance is checked by measuring portable tester.
the pump flow rate with a hydraulic tester installed at 11. Start the engine. Check the line connections for
the main pump delivery port (one side) to be meas- any oil leaks.
ured. Use Dr. EX and a pressure gauge at the same
time. Measurement:
1. Measure the maximum flow rate.
IMPORTANT: This measurement procedure is a 2. Select each switch position as follows:
simple method. The measured data Auto-Idle /
Engine Power Mode Work Mode
will be lower by approx. 5 % than the Acceleration
Control Dial Switch Switch
accurately measured value. To Selector
measure accurately, disconnect the Digging
return circuit from the control valve Fast Idle HP Mode OFF
Mode
and connect it to the hydraulic oil
tank. 3. Slowly close the loading valve of the hydraulic
tester while relieving the pressure. Measure the
Preparation: flow rates and engine speeds at the pressure
1. Stop the engine. Push the air bleed valve to bleed points specified in the P-Q curve.
air. Connect a vacuum pump to the oil filler port. 4. Repeat each measurement three times and cal-
NOTE: Operate the vacuum pump while connect- culate the average values.
ing the pump flow rate test line.
2. Disconnect the delivery hose from the main pump
(one side) to be measured. Connect pipe (1 or 2)
to the pump delivery port using the split flanges
and bolts which were used to connect the dis-
connected delivery hose.
: 41 mm : 10 mm
3. Connect hose (1 or 2) to hydraulic tester (5) using
test hose (3) and adapter (4). Connect adapter
(6), joint (7), test hose (8) and flange (9) to hy-
draulic tester (5).
: 41 mm : 10 mm
1. Connect the delivery hose to flange (9) with split
flanges (10) and bolts (11).
: 10 mm
1. Install a pressure gauge to the main pump to be
measured. (Refer to T4-4-8 Main Relief Pressure
Check.)
: 6 mm
1. Remove the pressure sensor (SA or SB) of the
main pump to measure.
(Pump 2: Remove 5-spool side pressure sensor
(SB)
Pump 1: Remove 4-spool side pressure sensor
(SA))
2. Remove the engine speed (N) sensor connectors.
3. Remove the P (delivery pressure) sensor from
the other main pump.
4. Disconnect the vacuum pump. Loosen drain plug
(12) on the top of the main pump to bleed the air
from the casing until oil comes out.

T4-5-14
 OPERATIONL PERFORMANCE TEST / Component Test
Evaluation:
1. Convert the measured flow rates to those at the 2. Standard Flow Rate
specified pump speed using the following formu- Refer to T4-2 Operational Performance Standard.
las:
NOTE: When actually measuring, install pipe (1 or
Qc = (Ns × Q) ⁄ (Ne × i) 2) only to the pump to be measured.

Qc : Converted Flow Rate

Q: Measured Flow Rate
-1
Ns : Specified Pump Speed (1800 min )
Ne : Measured Engine Speed
(When using the pulse counter: Pulse Numbers
(Hz) × 60 / 139)
i: Pump Drive Gear Speed Ratio
(Main Pump 1: 0.97, Main Pump 2: 1.0)

1, 2 3 4 5 6 7 8 9 10 11

Delivery Hose
(To Control
Valve)

T173-04-04-002

Signal Control Valve

Pump 2 Delivery
Pressure Sensor

Pump 1 Delivery
Pressure Sensor

12 T16J-01-01-003

5-Spool Side Pressure Sensor(SB)

4-Spool Side Pressure Sensor(SA) T16J-01-01-005

1- Pipe E (ST 6144) 4- Adapter PF1 × UNF1-7/8 (ST 6146) 7- Joint (ST 6330) 10- Split Flange (ST 6130)
2- Pipe B (ST 6143) 5- Hydraulic Tester (ST 6299) 8- Test Hose (ST 6320) 11- Bolt (ST 6409) (4 used)
3- Test Hose (ST 6145) 6- Adapter PF1 × UNF1-7/8 (ST 6146) 9- Flange (ST 6118) 12- Plug

T4-5-15
 OPERATIONL PERFORMANCE TEST / Component Test
Adjustment:

Adjustment of Minimum and Maximum Flow Rate NOTE: Turn screw (1) clockwise to decrease the
maximum flow rate and counterclockwise
Pump flow rate can be adjusted by changing the to increase. Turning screw (1) one forth a
maximum stroke of the servo piston. turn changes flow rate approximately 7.7
To adjust the maximum flow rate, loosen nut (2) and L/min (US gal.).
turn screw (1) on the large chamber side end of the Turn screw (4) clockwise to increase the
servo piston. minimum flow rate and counterclockwise to
To adjust the minimum flow rate, loosen nut (3) and decrease. Turning screw (4) one forth a
turn screw (4) on the small chamber side end of the turn changes flow rate approximately 7.7
servo piston. L/min (US gal.).

1 2 3 4

T16J-04-04-005

Maximum Flow Rate Adjustment Minimum Flow Rate Adjustment

Q Q

I I

NOTE: “I” Means Pump Control Solenoid Valve

Command Electrical Current Value

T4-5-16
 OPERATIONL PERFORMANCE TEST / Component Test
Flow Rate Control Setting Adjustment

Because the flow rate is controlled by the pump

control solenoid valve command electrical current(I), it
can be adjusted by changing set force of spring (5).
Loosen nut (6) and turn screw (7) to adjust spring (5)
setting.

5 6 7

T16J-04-04-006

Spring Setting Adjustment

Screw Turns 1/4 Flow Rate Control

27.6 L/min Q
Flow Rate
(US gal)

NOTE: “I” Means Pump Control Solenoid Valve

Command Electrical Current Value.

T4-5-17
 OPERATIONL PERFORMANCE TEST / Component Test
SWING MOTOR DRAINAGE
Summary:
To check swing motor performance, measure the
amount of oil draining from the swing motor while
swinging the upperstructure.

NOTE: The amount of drain oil from the swing

motor will change depending on the
hydraulic oil temperature. Be sure to
maintain hydraulic oil temperature at 50±5 1
°C (122±9°F).
A
Preparation:
1. Maintain hydraulic oil temperature at 50±5 °C
(122±9 °F). Rotate the swing motor to warm the B
inside of the motor.

CAUTION: The hydraulic oil tank cap may fly

off if turned quickly. Slowly turn it to release
internal pressure before removing it.
2
2. Move all control levers to release pressure
remaining in the system. Slowly turn the hydraulic
oil tank cap approximately 30 degrees
counterclockwise to release internal pressure
from the hydraulic oil tank.

: 4 mm

3. To measure the left swing motor drainage,

disconnect left swing motor drain hose (1) at part T16J-04-04-007
A. Install plug (ST 6491) on the tee side.

: 27 mm
: 93 Nxm (9.5 kgfxm, 70 lbfxft)

1. To measure the right swing motor drainage,

disconnect drain hose (2) at part B. Connect the
test drain hose (3/4-16UN) to the motor side and
plug (ST 6637) to drain hose (2).

: 27 mm
: 93 Nxm (9.5 kgfxm, 70 lbfxft)

Preconditions for Measurement:

CAUTION: Prevent personal injury. Always
Select the following switch positions:
make sure that the area is clear and that
co-workers are out of the swing area before
Auto-Idle /
starting machine operation. Engine Power Mode Work Mode
Acceleration
Also, take care not to fall off the machine Control Dial Switch Switch
Selector
while the measurement.
Digging
Fast Idle HP Mode OFF
Mode

T4-5-18
 OPERATIONL PERFORMANCE TEST / Component Test
Measurement:
1. Amount of Oil Drained While Swinging the
Upperstructure
(1) With the bucket empty, position the front
attachment as follows:
Backhoe:
With the arm cylinder fully retracted, and the
bucket cylinder fully extended, raise the
boom so that the arm tip pin heigh is flush
with the boom foot pin height.
T145-05-03-007
Loading Shovel:
With the arm cylinder and the bucket cylinder
fully extended, raise the boom so that the
arm tip pin height is flush with the boom foot
pin height.
(2) Start the engine. Operate and hold the swing
lever full stroke. Start draining oil
measurement after the swing speed eaches
a constant maximum speed. The measuring
time should be more than 20 seconds.
(3) Repeat the measurement three times in both
clockwise and counterclockwise directions, T145-05-03-008

and calculate the average values.

2. Amount of Oil Drained While Relieving Swing
Motor Circuit
(1) Thrust the bucket teeth into the ground as
illustrated so that the upperstructure does not
rotate when the swing lever is operated full
stroke.
(2) Start the engine. Operate and hold the swing T107-06-06-005

lever full stroke. Start drain oil measurement

when drain oil starts coming out of the drain
hose end. The measuring time should be
more than 20 seconds.
(3) Repeat the measurement three times in both
clockwise and counterclockwise directions,
and calculate the average values.
NOTE: Because the left swing motor drain hose is
connected to the right swing motor drain
port, the total of the left and right swing
motor drainage will be measured when
measuring the right swing motor drainage
according to step 4 in Preparation. For this
reason, be sure to deduct the amount of
left swing motor oil drainage (step 3 in
Preparation) from that total amount.

Evaluation: T107-06-05-008
Refer to the Performance Standard Table in Group
T4-2. ∆Q = 60 × q / t

∗ Conversion of the amount of drain oil measured Where:

into the per-minute value ∆Q : Amount of drain oil per minute (L/min)
First measure the amount of drain oil using a t : Time measured (seconds)
calibrated container. Then, convert the measured q : Total amount of drain oil (L)
drain oil into the per-minute value using the
formula below:

T4-5-19
 OPERATIONL PERFORMANCE TEST / Component Test
TRAVEL MOTOR DRAINAGE
Summary:
1. To check travel motor performance, measure the
amount of oil draining from the travel motor, while
rotating the travel motor with the measuring side
track jacked up.
2. During measuring, be sure to prevent personal
injury.
3. Evaluate the travel motor performance from Drain Hose
totaling the data.
4. The amount of drain oil from the travel motor and
the drain oil pressure will change depending on
hydraulic oil temperature.

Preparation:
1. Main hydraulic oil temperature at 50±5 °C (122±9
°F). Rotate the travel motor to warm the inside of
the motor.

CAUTION: The hydraulic oil tank cap may fly M183-01-001

off if turned quickly. Slowly turn it to release

internal pressure before removing it.

2. Move all control levers to release pressure

remaining in the system. Slowly turn the hydraulic
oil tank cap approximately 30 degrees
counter-clockwise to release internal pressure Test Drain Hose
from the hydraulic oil tank.

3. Disconnect the travel motor drain hose at the

travel motor side. Install plug (ST 6637) to the
disconnected hose end. Connect the test drain
hose (3/4-16UN) to the travel motor.

: 27 mm
T157-05-04-019

: 93 Nxm (9.5 kgfxm, 70 lbfxft)

Drain Hose
Preconditions for Measurement:
Select the following switch positions:

Auto-Idle / ST 6637
Engine Power Mode Work Mode
Acceleration
Control Dial Switch Switch
Selector
Digging
Fast Idle HP Mode OFF
Mode
T183-04-04-011

T4-5-20
 OPERATIONL PERFORMANCE TEST / Component Test
Measurement:

1. Start the engine. Jack up the measuring side

track using the front attachment, as illustrated.

CAUTION: Securely support the raised track

using wooden blocks.

2. Rotate the raised track with the travel lever

operated full stroke. Start drain oil measurement
after the track rotation speed reaches a constant
maximum speed. The measuring time should be T142-05-03-011

more than 20 seconds.

3. Repeat the measurement three times in both

forward and reverse directions and calculate the
average values.

Evaluation:
Refer to the Performance Standard Table in
Group T4-2.

∗ Conversion of the amount of drain oil measured

into the paramount value T142-05-03-012

First measure the amount of drain oil using a

calibrated container. Then, convert the
measured drain oil into the paramount value
using the formula below:

∆Q = 60 × q / t

Where:
∆Q : Amount of drain oil per minute (L/min)
t : Time measured (seconds)
q : Total amount of drain oil (L)

T157-05-04-019

T4-5-21
 OPERATIONL PERFORMANCE TEST / Component Test
(Blank)

T4-5-22
 OPERATIONAL PERFORMANCE TEST / Adjustment
INSTALLATION AND ADJUSTMENT OF
PUMP DISPLACEMENT SENSOR 1, 2

Removal
1. Put matching mark on the pump displacement
sensor and pump housing. Remove the pump
displacement sensor connector from its harness.

2. Remove two pump displacement sensor

mounting bolts (1) and washers (2).

3. Remove the pump displacement sensor. Take

care not to lose internal spacer (3) and fastener
spring (4). O-ring (5) is provided on the A sensor
side.
T111-04-05-001
Installation and Adjustment
1. Apply a film of grease to the surface of fastener 3
spring (4) and install it into the cavity on the
feedback shaft end. 4

2. With the key switch turned OFF, connect the

connector of the pump displacement sensor.
Then, connect the Dr. EX to the diagnosing
connector located in the operator's cab.

3. Start the engine and operate it in the slow idle

speed. T107-04-05-010

Pump
4. Operate Dr. EX. Select “Special Functions”, Displacement
Sensor
“Pump Adjustment”, and “Max. Disp. Holding” in
turn. The main pump is held at the maximum
displacement, and the monitor of Dr. EX displays
the output value of the pump displacement sensor.
(Refer to the page of Dr.EX Service Mode in 5
General group in TROUBLESHOOTING section.) 3
Punch Mark Feedback Shaft
5. With the punch mark on the pump displacement 4 T107-04-05-011

sensor shaft towards the opposite side of the

harness, turn the shaft so that the value on the Pump Pump
monitor may indicated as below. Displace- Displace-
ment ment
Pump 1 A/S Voltage: 1.60 V Sensor Sensor
Pump 2 A/S Voltage: 3.40 V (Pump 2) (Pump 1)

6. Install the pump displacement sensor to the pump.

Adjust the holes of the pump displacement
sensor so that the pump 1 A/S voltage or the
pump 2 A/S voltage may reach the specified
value.
Specified Value:
Pump 1 A/S voltage: 1.60 ± 0.02 V Harness
Pump 2 A/S voltage: 3.40 ± 0.02 V Harness Side
Side
7. Tighten bolts (1) and washers (2) to 9.8 Nxm (1.0
kgf⋅m, 7.2 lbf⋅ft). T16J-05-04-004

T4-6-1
 OPERATIONAL PERFORMANCE TEST / Adjustment
ENGINE SPEED ADJUSTMENT AND EN-
GINE LEARNING
After removing and/or replacing the components as
described below for repair and/or inspection, or if error
in engine speed is found, readjust engine speed and
perform engine learning.

• Removal of the engine, engine control cable, or

EC motor
• Replacement of MC

Adjustment of Engine Speed:

1. Turn the key switch to the START position to start
the engine.
NOTE: Turn the air conditioner OFF.
2. Rotate the engine control dial to the minimum
speed position. (The output voltage from the EC
sensor is 2.5 V.)
3. Deactivate the auto warming up and ECO control
systems by Dr. EX.
4. When Dr. EX is not available, keep the engine
running for about 15 minutes to warm coolant
temperature to more than 30 °C (86 F°) until the
auto warming up control system is deactivated.
5. Loosen the bolt holding the control lever to the
EC motor output shaft.
6. While monitoring the actual engine speed with Dr.
EX or the engine speed meter, adjust the control
lever so that the minimum speed (slow idle)
matches the specification.
Specification: Refer to T4-2-11.
7. Tighten the lever holding bolt to secure the con-
trol lever to the motor output shaft.
: 13 N⋅m (1.3 kgf⋅m, 9.4 lbf⋅ft)
Control
NOTE: Don’t lubricate the motor output shaft. Lever
8. Perform engine learning.

T16J-05-04-002
Holding Bolt

T4-6-2
 OPERATIONAL PERFORMANCE TEST / Adjustment
Engine Learning:
Rear Console
1. Turn the key switch OFF Fuse Box
NOTE: In case the engine doesn’t stop when the
key switch is turned OFF, pull the handle Engine
located under the seat to stop the engine. Learning
2. Disconnect Dr. EX. Wait for 5 seconds. Switch
3. Turn the engine learning switch ON.
4. Turn the key switch ON. Wait for 5 seconds.
5. Turn the key switch OFF. Wait for 5 seconds.
6. Turn the engine learning switch OFF.
7. Check the engine speed.

T178-01-02-006

T4-6-3
 OPERATIONAL PERFORMANCE TEST / Adjustment
CHECK OF GOVERNOR LEVER AND
FUEL CUT LEVER POSITION
Check the fuel cut lever position during cranking in
case of below.

• Although starter rotates, engine doesn’t start.

• Governor Lever and Fuel Cut Lever

1 2 3 4

T16J-04-02-008
1 - Fuel Cut Lever
2 - Fuel Cut-Off Cable
(Fuel Cut-Off Handle)
3 - Governor Lever
4 - Governor Cable
(From EC Motor)

T4-6-4
 OPERATIONAL PERFORMANCE TEST / Adjustment
• Governor Lever Position

A - Key Switch OFF (Engine Stop Position)

B - Key Switch ON (Engine Start Position)

B A
FULL STOP

STOP FULL

T16J-04-02-008

• Fuel Cut Lever Position

A - Fuel Cut-Off Handle Pulled Position

B - Fuel Cut-Off Handle Returned Position
A B

T16J-04-02-008

T4-6-5
 OPERATIONAL PERFORMANCE TEST / Adjustment
(Blank)

T4-6-6
 MEMO

....................................................................................................................................................................

....................................................................................................................................................................

....................................................................................................................................................................

....................................................................................................................................................................

....................................................................................................................................................................

....................................................................................................................................................................

....................................................................................................................................................................

....................................................................................................................................................................

....................................................................................................................................................................

....................................................................................................................................................................

....................................................................................................................................................................

....................................................................................................................................................................

....................................................................................................................................................................

....................................................................................................................................................................

....................................................................................................................................................................

....................................................................................................................................................................

....................................................................................................................................................................

....................................................................................................................................................................

....................................................................................................................................................................

....................................................................................................................................................................

....................................................................................................................................................................

....................................................................................................................................................................

....................................................................................................................................................................

....................................................................................................................................................................

....................................................................................................................................................................

....................................................................................................................................................................

....................................................................................................................................................................

....................................................................................................................................................................

....................................................................................................................................................................

....................................................................................................................................................................
 MEMO

....................................................................................................................................................................

....................................................................................................................................................................

....................................................................................................................................................................

....................................................................................................................................................................

....................................................................................................................................................................

....................................................................................................................................................................

....................................................................................................................................................................

....................................................................................................................................................................

....................................................................................................................................................................

....................................................................................................................................................................

....................................................................................................................................................................

....................................................................................................................................................................

....................................................................................................................................................................

....................................................................................................................................................................

....................................................................................................................................................................

....................................................................................................................................................................

....................................................................................................................................................................

....................................................................................................................................................................

....................................................................................................................................................................

....................................................................................................................................................................

....................................................................................................................................................................

....................................................................................................................................................................

....................................................................................................................................................................

....................................................................................................................................................................

....................................................................................................................................................................

....................................................................................................................................................................

....................................................................................................................................................................

....................................................................................................................................................................

....................................................................................................................................................................

....................................................................................................................................................................
 SECTION 5
TROUBLESHOOTING

CONTENTS
Group 1 General Group 3 Troubleshooting A
Introduction ............................................. T5-1-1 Troubleshooting A Procedure ................... T5-3-1
Diagnosing Procedure ............................. T5-1-2 Fault Code List ........................................ T5-3-2
Built-In Diagnosing System Operation...... T5-1-4 Fault Code 01, 02, 03 .............................. T5-3-3
Built-In Diagnosing Function Display List . T5-1-5 Fault Code 04 .......................................... T5-3-3
Dr. EX Operation ..................................... T5-1-6 Fault Code 05 .......................................... T5-3-3
Dr. EX Fault Code List ............................. T5-1-7 Fault Code 06 .......................................... T5-3-4
Dr. EX Monitoring Item List ...................... T5-1-8 Fault Code 07 .......................................... T5-3-5
Dr. EX Special Function ......................... T5-1-10 Fault Code 08, 09 .................................... T5-3-6
Dr. EX Service Mode ............................. T5-1-13 Fault Code 10, 11 .................................... T5-3-7
Adjustment Data List ............................. T5-1-24 Fault Code 12, 13 .................................... T5-3-8
Binary Number Bit List ........................... T5-1-27 Fault Code 14, 15, 16, 18 ........................ T5-3-9
Fault Code 19 ........................................ T5-3-10
Group 2 Component Layout Fault Code 20, 21 ...................................T5-3-11
Main Component Layout .......................... T5-2-1
Electrical Component Layout (Overview) . T5-2-2 Group 4 Troubleshooting B
Electrical System Troubleshooting B Procedure................... T5-4-1
(Relays and Related Equipment)............ T5-2-3 Relationship between Machine Trouble
Electrical System Symptoms and Related Parts ................. T5-4-2
(Monitors and Switches) ........................ T5-2-4 Correlation between Trouble
Engine ..................................................... T5-2-5 Symptoms and Part Failures ................ T5-4-16
Pump Device ........................................... T5-2-6 Engine System Troubleshooting............. T5-4-27
Swing Device........................................... T5-2-6 All Actuator System Troubleshooting ...... T5-4-42
Control Valve ........................................... T5-2-7 Front Attachment System
Signal Control Valve ................................ T5-2-7 Troubleshooting ................................... T5-4-48
Solenoid Valve Unit.................................. T5-2-8 Swing System Troubleshooting .............. T5-4-58
Travel Device........................................... T5-2-8 Travel System Troubleshooting .............. T5-4-61
Components in Control Valve................. T5-2-10 Other System Troubleshooting............... T5-4-68
Signal Control Valve Charge Air Conditioner with
Port Location ....................................... T5-2-14 Refrigerant........................................... T5-4-87
Exchange Inspection.............................. T5-4-95

16JT-5-1
Group 5 Troubleshooting C Group 7 ICX
Troubleshooting C Procedure .................. T5-5-1 Outline ..................................................... T5-7-1
Malfunction of Coolant ICX Fault Code List.................................. T5-7-6
Temperature Gauge ............................... T5-5-2 Satellite Terminal Fault Code List............. T5-7-6
Malfunction of Fuel Gauge ....................... T5-5-4 Fault Code 1 to 6 ..................................... T5-7-7
Malfunction of Indicator Light Fault Code 7 to 10 ................................... T5-7-7
Check System ....................................... T5-5-6 Some Parts of Data in Daily Report,
Malfunction of Preheat Indicator .............. T5-5-7 Frequency Distribution, Cumulative
Malfunction of Engine Oil Level Operation Hours are not Recorded......... T5-7-8
Indicator ................................................ T5-5-8 Troubleshooting and Setting of ICX and
Malfunction of Coolant Level Satellite Terminal Using Dr. EX ............ T5-7-10
Indicator .............................................. T5-5-10 Satellite Communication System.............T5-7-11
Malfunction of Alternator Indicator.......... T5-5-12
Malfunction of Engine Oil Pressure
Indicator .............................................. T5-5-14
Malfunction of Overheat Indicator .......... T5-5-16
Malfunction of Air Filter Restriction
Indicator .............................................. T5-5-18
Malfunction of Buzzer ............................ T5-5-20
Malfunction of LCD ................................ T5-5-22
Malfunction of Hour Meter...................... T5-5-23

Group 6 Electrical System Inspection

Precautions for Inspection and
Maintenance .......................................... T5-6-1
Instructions for Disconnecting
Connectors ............................................ T5-6-3
Fuse Inspection ....................................... T5-6-4
Fusible Link Inspection ............................ T5-6-5
Battery Voltage Check ............................. T5-6-5
How to Troubleshoot Alternator
Malfunctions .......................................... T5-6-6
Continuity Check ..................................... T5-6-7
Voltage and Current Measurement........... T5-6-8
Check by False Signal ............................T5-6-11
Test Harness ......................................... T5-6-12

16JT-5-2
 TROUBLESHOOTING / General
INTRODUCTION
Refer to the inspection and troubleshooting proce-
dures after any machine trouble has occurred. The
inspection and troubleshooting procedures are pre-
sented in an orderly fashion in this section to quickly
find the cause of the machine trouble and solution.

The troubleshooting section in this manual consists of

7 groups; General, Component Layout, Troubleshoot-
ing A (base machine diagnosis using fault codes),
Troubleshooting B (base machine diagnosis starting
with inspection of abnormal operational status), Trou-
bleshooting C (monitor diagnosis), Electrical System
Inspection, and ICX.

• General • Electrical System Inspection

Refer to this group when required to obtain pre-
• Component Layout cautions and/or information for the electrical sys-
tem inspection.
• Troubleshooting A (base machine diagnosis using
fault codes) Example: Fuse Inspection
Refer to these procedures if any fault codes are
displayed when the main controller (MC) is diag- • ICX
nosed with Dr. EX. (or the built-in diagnosing sys- Refer to these procedures after any fault code is
tem) displayed after diagnosing ICX (Information Con-
(MC self-diagnosing function retains a record of troller) or the satellite terminal (optional) with Dr.
the electrical signal system malfunction in the EX. (The controller self-diagnosing function re-
form of fault codes.) tains a record of the electrical signal system mal-
function in the form of fault codes.)
Example: Fault Code 06: Abnormal EC Sensor
Example: ICX Fault Code 7: MC Communication
• Troubleshooting B (base machine diagnosis start- Time Out
ing with inspection of abnormal operational
status) In addition, information on the following items is
Refer to these procedures when no fault codes described in this group.
are displayed after diagnosing the machine with 1. Trouble shooting and setting procedures of
Dr. EX (or the built-in diagnosing system). Trace ICX and satellite terminal using Dr. EX.
the cause of trouble based on the inspected result 2. Information on the satellite communication
of the abnormal symptom. system

Example: Even if the engine control dial is oper-

ated, engine speed remains unchanged.

• Troubleshooting C (monitor diagnosis)

Refer to these procedures when gauges and/or
indicators are malfunctioning.

Example: Malfunction of fuel gauge

T5-1-1
 TROUBLESHOOTING / General
DIAGNOSING PROCEDURE
These six basic steps are essential for efficient trou-
bleshooting:

1. Study the System

Study the machine’s technical manuals. Know the
system and how it works, and what the construc-
tion, functions and specifications of the system
components are.

1. Ask the operator T107-07-01-001

Before inspecting, get the full story of malfunc-
tions from your star witness…the operator.

(a) How is the machine being used? (Find out if

the machine is being operated correctly)

(b) When was the trouble noticed, and what

types of work the machine doing at that
time?

(c) What are the details of the trouble? Is the

trouble getting worse, or did it appear sud-
denly for the first time?

(d) Did the machine have any other troubles

previously? If so, which parts were repaired
before?

T107-07-01-002

1. Inspect the machine

Before starting the troubleshooting procedure,
check the machine’s daily maintenance points, as
shown in the operator's manual.

Also, check the electrical system, including the

batteries, as troubles in the electrical system such
as low battery voltage, loose connections and
blown fuses will result in malfunction of the con-
trollers, causing total operational failure of the
machine.
If troubleshooting is started without checking for
blown fuses, a wrong diagnosis may result, wast-
ing time. Be sure to check for blown fuses before
troubleshooting. Even if a fuse looks normal by
visual inspection, a fine crack is difficult to find.
Always use a tester when checking the fuses. T107-07-01-003

T5-1-2
 TROUBLESHOOTING / General
1. Operate the machine yourself
Try to identify the trouble by operating the ma-
chine yourself.
If the trouble cannot be confirmed, stop the en-
gine and obtain further details of the malfunction
from the operator.
Also, check for any incomplete connections of the
wire harnesses.

1. Perform troubleshooting
CAUTION: Never attempt to disconnect har- T107-07-01-004

nesses or hydraulic lines while the engine is

running. The machine may malfunction or
pressurized oil may spout, possibly resulting
in personal injury. Be sure to stop the engine
before disconnecting harnesses or hydraulic
lines.

Perform self-diagnosis by connecting Dr. EX to

the machine or by operating the built-in
self-diagnosing system. In case any fault code
has been displayed by diagnosis using Dr. EX (or
the built-in self-diagnosing system), delete the
fault code once and retry self-diagnosis again. If
the fault code is displayed again, check the cause T107-07-01-005

of the trouble by referring to Troubleshooting A in

this section. After the machine trouble has been
corrected, the fault code (displayed by the built-in
self-diagnosing function) will be deleted. There-
fore, in case problems which are not easily
re-predicable are encountered, use Dr. EX to dis-
play the fault code. In case no fault codes are
displayed, check all related parts/component
operating condition using the monitor function of
Dr. EX (or the built-in self-diagnosing system)
while referring to troubleshooting B in this section.

※Note that the fault codes displayed do not nec-

essarily indicate machine trouble. The controller
stores even temporary electrical malfunctions,
such as a drop in battery output voltage or dis- T107-07-01-006

connections of the switches, sensors, etc., for

inspections.
For this reason, the “RETRIAL” is required to
erase the accumulated fault codes from the con-
troller memory and to confirm if any fault codes
are indicated after the “RETRIAL”.

1. Trace possible causes

Before reaching a conclusion, check the most
likely causes again. Try to identify the actual
cause of the trouble.
Based on your conclusion, make a plan for ap-
propriate repairs to avoid consequent malfunc-
tions. T107-07-01-007

T5-1-3
 TROUBLESHOOTING / General
BUILT-IN DIAGNOSING SYSTEM OPERA-
TION
IMPORTANT: This system is to be operated by the
HITACHI Dealer Only. Don’t explain
this system function to the customer.

In the service mode, the monitor LCD displays the di-

agnosing items, fault codes and monitored results (not
all of them) without using Dr. EX.

Built-In Diagnosing System Activation

While pressing the monitor SET switch, turn the key
Display Selection
switch ON. Switch

Built-In Diagnosing System Operation SET Switch

Each time the display selection switch is pressed, the
displayed item will be changed as shown on next
page.

NOTE: The fault code is indicated in the display

order 8. All fault codes (21 in total) can be LCD
indicated. In case more than one fault code
is indicated, they will be displayed with an
interval of 1 second in order. After the ma-
chine malfunction has been repaired, the
fault codes are automatically deleted. Ac-
cordingly, if any trouble, which is not re- M16J-01-010

producible, is encountered, it is recom-

mended to use Dr. EX.
• The built-in diagnosing system displays only the
item No. on the left and the monitored result on the
right. The item description is not displayed.

T5-1-4
 TROUBLESHOOTING / General
BUILT-IN DIAGNOSING FUNCTION DISPLAY LIST

Display
Description Monitored Result Unit Remarks
Order
1 Hour Meter {{{{{ h Standard Mode
2 Trip 1 {{{{{ h Standard Mode (Subtraction)
3 Trip 2 {{{{{ h Standard Mode (Subtraction)
4 Engine Actual Speed n {{{{ -1 User Mode (Required to set
min
in the Dr. EX service mode)
5 Hydraulic Oil Tempera- {{{ °C User Mode (Required to set
ture in the Dr. EX service mode)
6 L1 {{{ － Display Purpose Only
7 L2 {{{ % Display Purpose Only
8 Fault Code* 0 {{ － Possible to display
9 1 {{ 0: Switch OFF Display Purpose Only
1: Switch ON
10 Pump 1 Delivery Pres- 2 {{ MPa Possible to display
sure
11 Pump 2 Delivery Pres- 3 {{ MPa Possible to display
sure
12 Pump 1 Pump (Flow) 4 {{ MPa Possible to display
Control Pressure
13 Pump 2 Pump (Flow) 5 {{ MPa Possible to display
Control Pressure
-1
14 Engine Target Speed 6 {{ min Possible to display
15 EC Angle 7 {{ V Possible to display
16 Dial Angle 8 {{ V Possible to display
17 Boom Raise Pilot Pres- 9 {{ MPa Possible to display
sure
18 Arm Roll-In Pilot Pres- A {{ MPa Possible to display
sure
19 Swing Control Pilot b {{ MPa Possible to display
Pressure
20 Travel Control Pilot c {{ MPa Possible to display
Pressure
21 Front Att. Operation d {{ 0: Not Operating Possible to display
1: Operating
22 Att. Control Pressure E {{ MPa Possible to display
23 Work Mode F {{ 0: Digging Display Purpose Only
1: Breaker
2: Secondary
Crusher
(Demolisher)
3: Crusher
4: Vibro-Hammer

NOTE: *: Refer to T5-1-7 for the Fault Codes.

T5-1-5
 TROUBLESHOOTING / General
Dr. EX OPERATION
Rear Console
Dr. EX is a troubleshooting tool to diagnose the elec- Fuse Box
tronic control system including the MC (main Control-
ler) and ICX (Information Controller). When Dr. EX is
Dr. EX Connector
connected to either the MC or the ICX, it displays (MC)
whether the controllers and sensors operate normally
in the form of fault codes (Self-Diagnosing Result Dis-
play Function).
In addition, Dr. EX can display the inputs from sensors
and switches to the MC and/or the outputs to actuators
such as solenoid valves from the MC in real time while
operating the machine (Monitor Display Function).

NOTE: This group describes how to operate Dr.

EX connected to the MC. Refer to Group 7
“ICX” for operation of Dr. EX connected to
the ICX. Dr. EX Connector
(ICX)
Operation
1. Connect the Dr. EX harness to the diagnosis con- T178-01-02-006
nector in the cab.
IMPORTANT: The Dr. EX harness functions the Start
self-diagnosing switch so that be
sure to use the specified one.
1. Turn the key switch ON, or start the engine.
2. When the Dr. EX power is turned ON, Dr. EX dis- Title Screen
plays the following screens in order.
1-1. Title Screen
1-2. Model Name Screen
Model Name
(Example) Model: ZX450 Cannot Confirmation
1-3. Function Selection Screen Communicate
F1: Self-Diagnosing Result
· Check harness.
F2: Monitor Display NOT OK
· Check fuse.
F3: Special Functions OK ?

NOTE: Special functions allow the ECO, WU de- OK

Replace software.
activation and pump adjustment. (Refer to
T5-1-10)
Self-Diagnosing
4. Select F1. Then, continue to operate Dr. EX by Result Display Special
following instructions to be displayed at the Function Select Monitor Function
screen bottom hereafter. function.

NOTE: Refer to the Dr. EX Operation Manual for Self-diagnosing

the detailed operation of Dr. EX. result by controller Select data to
is displayed. Record.
be monitored.

Monitored data
Retry B is displayed.

Self-diagnosing re-
sult is displayed.

T5-1-6
 TROUBLESHOOTING / General
Dr. EX FAULT CODE LIST

Fault Code Trouble Cause

01 Abnormal EEPROM • Faulty MC
02 Abnormal RAM
03 Abnormal A/D Conversion
04 Abnormal Sensor Voltage • Faulty MC
• Faulty Sensor
05 Abnormal N Sensor • Faulty N Sensor
06 Abnormal EC Sensor • Faulty MC
• Faulty Harness
• Faulty EC Sensor
07 Abnormal Engine Control Dial Angle • Faulty MC
• Faulty Harness
• Faulty Engine Control Dial
08 Abnormal Pump 1 Displacement Angle • Faulty MC
09 Abnormal Pump 2 Displacement Angle • Faulty Harness
• Faulty Pump Displacement Angle Sensor
10 Abnormal Pump 1 Delivery Pressure • Faulty MC
11 Abnormal Pump 2 Delivery Pressure • Faulty Harness
• Faulty Pump Delivery Pressure Sensor
12 Abnormal Pump1 Pump Control Pressure • Faulty MC
13 Abnormal Pump2 Pump Control Pressure • Faulty Harness
• Faulty (Pump Control) Pressure Sensor (SA, SB)
14 Abnormal Swing Pilot Pressure • Faulty MC
15 Abnormal Boom Raise Pilot Pressure • Faulty Harness
16 Abnormal Arm Roll-In Pilot Pressure • Faulty Pilot Pressure Sensor
18 Abnormal Travel Pilot Pressure
19 Abnormal Hydraulic Oil Temperature • Faulty MC
• Faulty Harness
• Faulty Hydraulic Oil Temperature Sensor
20 Pump1 Control Malfunction • Faulty MC
21 Pump2 Control Malfunction • Faulty Harness
• Faulty Pump Control Solenoid Valve
• Faulty Pump Displacement Angle Sensor

T5-1-7
 TROUBLESHOOTING / General
Dr. EX MONITORING ITEM LIST
Dr. EX displays the input signals from the switches
and sensors to the MC and the control signals to the
actuators from the MC.

Item Data Unit

Pump 1 Delivery Pressure Input signals from pump 1 delivery pressure sensor MPa
Pump 1 Flow Control Pres- Input signals from pump 1 control pressure sen- MPa
sure sor(SA)
3
Pump 1 Actual Displace- Input signals from pump 1 displacement angle sensor cm
ment
3
Pump 1 Desired Displace- Desired displacement for pump 1 cm
ment
Pump 1 Desired Torque Nxm
Pump 2 Delivery Pressure Input signals from pump 2 delivery pressure sensor MPa
Pump 2 Flow Control Pres- Input signals from pump 2 control pressure sen- MPa
sure sor(SB)
3
Pump 2 Actual Displace- Input signals from pump 2 displacement angle sensor cm
ment
3
Pump 2 Desired Displace- Desired displacement for pump 2 cm
ment
Pump 2 Desired Torque Nxm
Sensor Power Source Volt- NORMAL, LOW
age
Power Boost Switch Power digging switch status P/B
-1 -1
Engine Target Speed Target speed when loaded. Approx. 150 min differs min
from speed when unloaded.
-1
Engine Actual Speed Input signal from N sensor min
-1
Engine Speed Differential Calculated Value min
( Target engine speed - Actual engine speed)
EC Angle Input signal from EC sensor V
Dial Angle Input signal from engine control dial V
Boom Raise Pilot Pressure Input signal from pressure sensor (boom raise) MPa
Arm Digging Pilot Pressure Input signal from pressure sensor (arm roll-In) MPa
Aux. 1 Input Voltage V
Swing Control Pressure Input signal from pressure sensor (swing) MPa
Travel Control Pressure Input signal from pressure sensor (travel) MPa
Att. Control Pilot Pressure Input signal from pressure sensor (front att.) MPa
Swing/Front Attachment Pressure sensor (swing and front att) status Sw/Fr
Ope.
C/W Remove Cont. Pilot Input signal from pressure sensor (c/w remove) MPa
Press.
Hydraulic Oil Temperature Input signal from oil temperature sensor °C
Eng. Overheat Switch Eng. overheat switch status NORMAL,
OVERHEAT
E/P/HP Mode Switch Power mode switch selection status E, P, HP
Auto-Idle/Auto-Accel Switch Auto-Idle/Acceleration selection status AI, AA
Travel Mode Travel mode switch selection status Lo, Hi
Key Switch Key switch selection status Ky
Work mode Work mode switch selection status GENERAL,
TRENCH, ATT

T5-1-8
 TROUBLESHOOTING / General

Item Data Unit

Attachment Mode Attachment mode switch selection status BRK1,BRK2,
BRK3
Engine Learning Status OK, NG,
ABORTED
Boom Mode Selector Boom mode selector switch status BM/M
Precision Mode Switch Precision mode switch status PR/M
Boom Mode Control Valve MPa
Out.
Power Boost Control Valve MPa
out.
Travel Motor Control Valve MPa
Out.
Swing/Boom Control Valve MPa
Out.
Aux. 2 Input Voltage V
Lubrication Selector Signal ABV, STD,
COLD, LSW
Lubrication Control Status OK, NG
Lubrication Control Output HALT, FWD,
REV
Travel/Swing Alarm Tr, Sw
Boom Cyl. Bottom Pressure MPa

T5-1-9
 TROUBLESHOOTING / General
Dr. EX SPECIAL FUNCTION

HITACHI
Special function related to Dr.EX screen panels,

Dr.EX
beginning with the start screen, are shown along
VER
**** with the corresponding Dr.EX key operations.
However, Dr.EX screen panels which are not
related to the Dr.EX key operation are excluded.
(C)Hitachi Construction
Machinery Co.,Ltd. 1996
F1: Start F10: Model Menu

F1 Press

Model : ZX450

Ver : 0201

Is model correct?
F1: Correct F10: ESC

F1 Press

Select Functions

F1: Self-Diagnostic Results

F2: Monitor Display
F3: Special Functions 2

F5: ESC

F3 Press

T5-1-10
 TROUBLESHOOTING / General

1 2

F5 Press

Select Functions WU Deactivation?

F6: WU Deactivation
F6 Press
F7: ECO Deactivation Push Key F1 or F5
F8: Pump Adjustment

F5: ESC F1:Execute F5:ESC

F8 Press

F7 Press F1 Press
3

ECO Deactivation WU Deactivation

Succeeded

Push Key F1 or F5

F1: Execute F5: ESC F5: ESC

F1 Press

ECO Deuctivation
Succeaded

F5: ESC

T5-1-11
 TROUBLESHOOTING / General

Select Functions

F6: Max. Disp. Holding

F7:
F8:

F5: ESC

F6 Press

Displacement is Held at Maximum

Check A/S Fixing

Pump 1 A/S Voltage 1.56 V

Pump 2 A/S Voltage 3.42 V

F5: ESC

T5-1-12
 TROUBLESHOOTING / General
Dr. EX SERVICE MODE
Dr. EX has four (4) modes, learning data display,
monitor display change, parameter change, activation
/ deactivation of parameter change.

Learning Data Display

Displays the values set by learning function.

Monitor Display Change

Items to be displayed on the monitor LCD can be
added.

Parameter Change
Engine speed, pump delivery flow rate, and solenoid
valve output pressure can be adjusted.

Activation/Deactivation of parameter change

Rear Console
All items except engine changed in parameter change Fuse Box
are turned into either activation or deactivation (stan-
Engine
dard). Learning
In case activation is selected, the value changed in Switch
parameter change isn’t cleared.

• Accessing Service Mode

1. After turning the key switch OFF, wait for more
than 10 seconds.
2. Connect Dr. EX to the connector on the base
machine.
3. Turn the engine learning switch to the learning
position (the E mark side).
4. Turn the key switch ON. Don’t start the engine at
this time.
5. Turn Dr. EX switch ON.

T178-01-02-006

T5-1-13
 TROUBLESHOOTING / General

Item Data
Learning Data Display
EC Motor Stop Position Display of the engine stop value in engine learning
EC Motor Maximum Speed Position Display of max. engine speed valve in engine learning
Parameter Change
Li Speed Adjustment Adjustment of minimum engine speed
WU Speed Adjustment Adjustment of warming up engine speed
AI Speed Adjustment Adjustment of auto-idle engine speed
E Speed Adjustment Adjustment of E-mode engine speed
P Speed Adjustment Adjustment of P-mode engine speed
ATT Speed lncrease Down Wating Time Setting of time required for engine speed increase
Breaker 1 Engine Speed Adjustment Adjustment of breaker 1 operation engine speed
Breaker 2 Engine Speed Adjustment Adjustment of breaker 2 operation engine speed
Breaker 3 Engine Speed Adjustment Adjustment of breaker 3 operation engine speed
Breaker 4 Engine Speed Adjustment Adjustment of breaker 4 operation engine speed
Lubricator Max. Compressing Time The maximum valve of the auto-lubricator compressing time at one cycle
Lubrication Interval (INCREASE) The interval valve of the auto-lubrication (INCREASE) operated time
Lubrication Interval (STANDARD) The interval valve of the auto-lubrication (STANDARD) operated time
Lubrication Interval (COLD WEATHER) The interval valve of the auto-lubrication (COLD WEATHER) operated time
Pump 1 Cut-off Pressure Adjustment Adjustment of pump1 cut-off pressure
Pump 1 Cut-off Operating Lever Operation The lever stroke corresponding to the cut-off pressure of pump 1 as above
Pump 2 Cut-off Pressure Adjustment Adjustment of pump2 cut-off pressure
Pump 2 Cut-off Operating Lever Operation The lever stroke corresponding to the cut-off pressure of pump 2 as above
Standard Mode Pump 1 Max. Displacement The valve to control the maximum displacement of pump 1 at work mode, “Dig-
ging”
Trenching Mode Pump 1 Max. Displacement The valve to control the maximum displacement of pump 1 at work mode,
“Trenching”
Breaker 1 Pump 1 Max. Displacement The valve to control the maximum displacement of pump 1 at ATT mode, “BRK1”
Breaker 2 Pump 1 Max. Displacement The valve to control the maximum displacement of pump 1 at ATT mode, “BRK2”
Breaker 3 Pump 1 Max. Displacement The valve to control the maximum displacement of pump 1 at ATT mode, “BRK3”
Breaker 4 Pump 1 Max. Displacement The valve to control the maximum displacement of pump 1 at ATT mode, “BRK4”
Standard Mode Pump 2 Max. Displacement The valve to control the maximum displacement of pump 2 at work mode, “Dig-
ging”
Trenching Mode Pump 2 Max. Displacement The valve to control the maximum displacement of pump 2 at work mode,
“Trenching”
Breaker 1 Pump 2 Max. Displacement The valve to control the maximum displacement of pump 2 at ATT mode, “BRK1”
Breaker 2 Pump 2 Max. Displacement The valve to control the maximum displacement of pump 2 at ATT mode, “BRK2”
Breaker 3 Pump 2 Max. Displacement The valve to control the maximum displacement of pump 2 at ATT mode, “BRK3”
Breaker 4 Pump 2 Max. Displacement The valve to control the maximum displacement of pump 2 at ATT mode, “BRK4”
All Mode Pump 1 and 2 Max. Reference Torque Total The valve to control the maximum standard torque total of pumps 1 and 2 at all
work mode
Breaker 1 Pump 1 and 2 Max. Reference Torque To- The valve to control the maximum standard torque total of pumps 1 and 2 at ATT
tal mode, “BRK1”
Breaker 2 Pump 1 and 2 Max. Reference Torque To- The valve to control the maximum standard torque total of pumps 1 and 2 at ATT
tal mode, “BRK2”
Breaker 3 Pump 1 and 2 Max. Reference Torque To- The valve to control the maximum standard torque total of pumps 1 and 2 at ATT
tal mode, “BRK3”
Breaker 4 Pump 1 and 2 Max. Reference Torque To- The valve to control the maximum standard torque total of pumps 1 and 2 at ATT
tal mode, “BRK4”
All Mode Pump 2 Max. Desired Torque The valve to control the maximum desired torque of pump 2 at all work mode
Breaker 1 Pump 2 Max. Desired Torque The valve to control the maximum desired torque of pump 2 at ATT mode,
“BRK1”
Breaker 2 Pump 2 Max. Desired Torque The valve to control the maximum desired torque of pump 2 at ATT mode,
“BRK2”
Breaker 3 Pump 2 Max. Desired Torque The valve to control the maximum desired torque of pump 2 at ATT mode,
“BRK3”
Breaker 4 Pump 2 Max. Desired Torque The valve to control the maximum desired torque of pump 2 at ATT mode,
“BRK4”
Monitor Display Change
Engine Actual Speed Display/Non-display Monitor setting of display/no-display of actual engine speed
Hydraulic Oil Temperature Display/No-display Monitor setting of display/no-display of hydraulic oil temperature

T5-1-14
 TROUBLESHOOTING / General

HITACHI
Service mode related to Dr.EX screen panels,

Dr.EX VER
****
beginning with the start screen, are shown along
with the corresponding Dr.EX key operations.
However, Dr.EX screen panels which are not
(C)Hitachi Construction related to the Dr.EX key operation are excluded.
Machinery Co.,Ltd. 1996
F1: Start F10: Model Menu

F1 Press

Model : ZX450

Ver : 0201

Is model correct?
F1: Correct F10: ESC

F1 Press

Service mode selected.

In service mode, self-diagnostic

operation and/or monitor display
will not be conducted.

F1: Rechecked F5: ESC

F1 Press

T5-1-15
 TROUBLESHOOTING / General

Select Function

F3: Special Functions

F5: ESC

F3 Press

Select Functions F6 Press Select Learning Data to be

Displayed
F6: Learning Data Display
F7: Monitor Display Change F6: EC Motor Stop Position
F8 Press
F8: Parameter Change F7: EC Motor Maximum Speed
6 Position
11
F3: NEXT F5: ESC F3 Press F5:ESC

7
F7 Press F6 Press

Select Item

F6: Eng. Act.Speed EC Motor Stop Position Learning

F7: Hyd. Oil Temp. data
F8: -519 digit is
5 displayed
F5:ESC F5: ESC

F6 Press An example of ‘‘F6: Eng. Act. Speed’’

operation is shown on the next page.

Eng. Act. Speed

F1: Appear F2: Hide

F5: ESC

F2 Press
F1 Press

2 3

T5-1-16
 TROUBLESHOOTING / General

2 3

∗∗ Confirmation ∗∗ ∗∗ Confirmation ∗∗

Eng. Act. Speed Eng. Act. Speed

Monitor: Appear Monitor: Hide

F1: Excute F5: ESC F1: Execute F5: ESC

F1 Press F1 Press

Eng. Act. Speed Eng. Act. Speed

Monitor: Appear Monitor: Hide

5 5
F5: ESC F5: ESC

F5 Press F5 Press

T5-1-17
 TROUBLESHOOTING / General

Select Functions An example of ‘’Li speed

adjustment’’ operation is shown on
F6: Li Speed Adjustment the T5-1-20.
8
F7: WU Speed Adjustment F6 Press
F8: AI Speed Adjustment

10
F3: NEXT F5: ESC

F3 Press

Select Functions
F6: Lubricaiton Interval
Select Functions (COLD WEATHER)
F7: Pump 1 Cut-Off Pressure
F6: E Speed Adjustment Adjustment
F7: P Speed Adjustment F8: Pump 1 Cut-Off Working
F8: ATT Speed Increase Down Operation
Waiting Time F3: Next F4: Prev. F5: ESC

F3: Next F4: Prev. F5: ESC F3 Press

F3 Press
Select Functions
F6: Pump 2 Cut-Off Pressure
Select Fuctions Adjustment
F6: BRK 1 Engine Speed F7: Pump 2 Cut-Off Working
Adjustment Operation
F7: BRK 2 Engine Speed F8: GENERAL Max. Pump 1
Adjustment Displacement
F8: BRK 3 Engine Speed F3: Next F4: Prev. F5: ESC
Adjustment
F3: Next F4: Prev. F5: ESC F3 Press

F3 Press Select Functions

F6: TRENCH Max. Pump 1
Select Functions Displacement
F6: Lubricator Max F7: BRK 1 Max. Pump 1
Compressing Time Displacement
F7: Lubrication Interval F8: BRK 2 Max. Pump 1
(INCREASE) Displacement
F8: Lubrication Interval F3: Next F4: Prev. F5: ESC
(STANDARD)
F3: Next F4: Prev. F5: ESC F3 Press

12
F3 Press Next Page

T5-1-18
 TROUBLESHOOTING / General

12

Select Functions
F6: BRK 3 Max. Pump 1
Displacement
F7: GENERAL Max. Pump 2 Select Functions
Displacement F6: BRK 3 Max. Pump Ref.
F8: TRENCH Max. Pump 2 Torque Total
Displacement F7: All Mode Max. Pump 2
F3: Next F4: Prev. F5: ESC Desired Torque
F8: BR1 Max. Pump 2 Desired
Torque
F3 Press F3: Next F4: Prev. F5: ESC

F3 Press
Select Functions
F6: BRK 1 Max. Pump 2 Select Functions
Displacement
F7: BRK 2 Max. Pump 2 F6: BRK 2 Max. Pump 2 Desired
Displacement Torque
F8: BRK 3 Max. Pump 2 F7: BRK 3 Max. Pump 2 Desired
Displacement Torque
F3: Next F4: Prev. F5: ESC F8:
F3: Next F4: Prev. F5: ESC
F3 Press

Select Fuctions
F6: All Mode Max. Pump Ref.
Torque Total
F7: BRK 1 Max. Pump Ref.
Torque Total
F8: BRK 2 Max. Pump Ref.
Torque Total
F3: Next F4: Prev. F5: ESC

F3 Press

T5-1-19
 TROUBLESHOOTING / General

Li Speed Adjustment

Adjustable Range in HELP Input

the Adjusting Deviation you want.

F3: Next F4: Prev. F5: ESC

F3 Press

Li Speed Adjustment
-1
Current: 0 min
-1
Adjustment: min

F1: Execution F2: corr

F4: Prev. F5: ESC F7: HELP “+20” is entered as an example here.

SFT
SFT Press

+
Press
2

SFT
Press
SFT

+
Press
2

°
Press
0

*Adjusting Deviation*
*Data Confirmation*

Adjusting Deviation Data

Name:
Li Speed Adjustment

F3: Next F5: ESC

F3 Press

13
Next Page

T5-1-20
 TROUBLESHOOTING / General

13

-1
Current : 0 min
-1
Adjustment : +20 min

F1: Exeute F4: Prev. F5: ESC

F1 Press

Adjustment was made as

Follows:

Adjusting Deviation Data Name:

Li Speed Adjustment

F3: Next

F3 Press

-1
Current: 0 min
-1
Adjustment: +20min

10
F4: Prev. F5: ESC

F5 Press

T5-1-21
 TROUBLESHOOTING / General

Select Functions

F6: Activation/Deactivation of All items except engine changed in Parameter

Parameter Change Change are turned into either activation or
F7: 11 deactivation (standard).
In case activation is selected, the value changed
F8: in Parameter Change isn’t cleared.
F4: Prev. F5: ESC

F6 Press

Select Functions F1 or F2

F1: Activation of Parameter

Except Engine
F2: Deactivation of Parameter
Except Engine

F5: ESC

F2 Press
F1 Press

Activation of Parameter Except Deactivation of Parameter except

Engine Suceeded. Engine Succeeded.

11 11
F5: ESC

F5 Press F5 Press

T5-1-22
 TROUBLESHOOTING / General
• Operational Performance Check After Adjustment
(Check that pump flow rate and engine speed
have been changed.)

IMPORTANT: After adjusting the engine speed

and flow rate to the attachment, turn
the engine learning switch to neutral.
If the engine is started with the en-
gine learning switch in the engine
learning position, the MC will not
control the engine, pumps, and
valves so that change in the pump
flow rate and the engine speed
cannot be checked.

1. Turn the key switch OFF.

2. Wait approx. 10 seconds.
3. Turn the engine learning switch to neutral.
4. Disconnect the Dr. EX. connector (When moni-
toring with Dr. EX, pass this step.)
5. Turn the key switch ON.
6. Start the engine.
7. Check operational performances of the machine.

T5-1-23
 TROUBLESHOOTING / General
ADJUSTMENT DATA LIST

Adjustable Standard
Adjustment Data Data
Range Adjustment
-1
Li Speed Adjustment Adjustment of minimum engine speed 0 to 120 0 min
-1
WU Speed Adjustment Adjustment of warming up engine speed -80 to 120 0 min
-1
AI Speed Adjustment Adjustment of auto-idle engine speed -120 to 120 0 min
-1
E Speed Adjustment Adjustment of E-mode engine speed -120 to 120 0 min
-1
P Speed Adjustment Adjustment of P-mode engine speed -120 to 100 0 min
ATT Speed lncrease Down Setting of time required for engine speed in- 0 to 3000 0 msec
Wating Time crease
-1
Breaker 1 Engine Speed Adjustment of breaker 1 operation engine -500 to 100 0 min
Adjustment speed
-1
Breaker 2 Engine Speed Adjustment of breaker 2 operation engine -500 to 100 0 min
Adjustment speed
-1
Breaker 3 Engine Speed Adjustment of breaker 3 operation engine -500 to 100 0 min
Adjustment speed
-1
Breaker 4 Engine Speed Adjustment of breaker 4 operation engine -500 to 100 0 min
Adjustment speed
Lubricator Max. Com- The maximum valve of the auto-lubricator 5 to 7 7 min
pressing Time compressing time at one cycle
Lubrication Interval The interval valve of the auto-lubrication 10 to 90 60 min
(INCREASE) (INCREASE) operated time
Lubrication Interval The interval valve of the auto-lubrication 10 to 90 90 min
(STANDARD) (STANDARD) operated time
Lubrication Interval (COLD The interval valve of the auto-lubrication 10 to 90 90 min
WEATHER) (COLD WEATHER) operated time
Pump 1 Cut-off Pressure Adjustment of pump1 cut-off pressure -18.81 to 0 0 MPa
Adjustment
Pump 1 Cut-off Operating The lever stroke corresponding to the cut-off *1
Lever Operation pressure of pump 1 as above
Pump 2 Cut-off Pressure Adjustment of pump2 cut-off pressure -18.81 to 0 0 MPa
Adjustment
Pump 2 Cut-off Operating The lever stroke corresponding to the cut-off *1
Lever Operation pressure of pump 2 as above
3
Standard Mode Pump 1 The valve to control the maximum displace- 54.4 to 204 204 cm
Max. Displacement ment of pump 1 at work mode, “Digging”
3
Trenching Mode Pump 1 The valve to control the maximum displace- 54.4 to 204 204 cm
Max. Displacement ment of pump 1 at work mode, “Trenching”
3
Breaker 1 Pump 1 Max. The valve to control the maximum displace- 54.4 to 204 204 cm
Displacement ment of pump 1 at ATT mode, “BRK1”
3
Breaker 2 Pump 1 Max. The valve to control the maximum displace- 54.4 to 204 204 cm
Displacement ment of pump 1 at ATT mode, “BRK2”
3
Breaker 3 Pump 1 Max. The valve to control the maximum displace- 54.4 to 204 204 cm
Displacement ment of pump 1 at ATT mode, “BRK3”
3
Breaker 4 Pump 1 Max. The valve to control the maximum displace- 54.4 to 204 204 cm
Displacement ment of pump 1 at ATT mode, “BRK4”
3
Standard Mode Pump 2 The valve to control the maximum displace- 54.4 to 204 204 cm
Max. Displacement ment of pump 2 at work mode, “Digging”
3
Trenching Mode Pump 2 The valve to control the maximum displace- 54.4 to 204 204 cm
Max. Displacement ment of pump 2 at work mode, “Trenching”
NOTE: 1 MPa = 98.07 kPa
1 kgf⋅m = 9807 N⋅m
*1: Refer to T5-1-26.

T5-1-24
 TROUBLESHOOTING / General

Adjustable Standard
Adjustment Data Data
Range Adjustment
3
Breaker 1 Pump 2 Max. The valve to control the maximum displace- 54.4 to 204 204 cm
Displacement ment of pump 2 at ATT mode, “BRK1”
3
Breaker 2 Pump 2 Max. The valve to control the maximum displace- 54.4 to 204 204 cm
Displacement ment of pump 2 at ATT mode, “BRK2”
3
Breaker 3 Pump 2 Max. The valve to control the maximum displace- 54.4 to 204 204 cm
Displacement ment of pump 2 at ATT mode, “BRK3”
3
Breaker 4 Pump 2 Max. The valve to control the maximum displace- 54.4 to 204 204 cm
Displacement ment of pump 2 at ATT mode, “BRK4”
All Mode Pump 1 and 2 The valve to control the maximum standard 773 to 1145 1145 N⋅m
Max. Reference Torque torque total of pumps 1 and 2 at all work mode
Total
Breaker 1 Pump 1 and 2 The valve to control the maximum standard 773 to 1145 1145 N⋅m
Max. Reference Torque torque total of pumps 1 and 2 at ATT mode,
Total “BRK1”
Breaker 2 Pump 1 and 2 The valve to control the maximum standard 773 to 1145 1145 N⋅m
Max. Reference Torque torque total of pumps 1 and 2 at ATT mode,
Total “BRK2”
Breaker 3 Pump 1 and 2 The valve to control the maximum standard 773 to 1145 1145 N⋅m
Max. Reference Torque torque total of pumps 1 and 2 at ATT mode,
Total “BRK3”
Breaker 4 Pump 1 and 2 The valve to control the maximum standard 773 to 1145 1145 N⋅m
Max. Reference Torque torque total of pumps 1 and 2 at ATT mode,
Total “BRK4”
All Mode Pump 2 Max. The valve to control the maximum desired 386 to 819 819 N⋅m
Desired Torque torque of pump 2 at all work mode
Breaker 1 Pump 2 Max. The valve to control the maximum desired 386 to 819 819 N⋅m
Desired Torque torque of pump 2 at ATT mode, “BRK1”
Breaker 2 Pump 2 Max. The valve to control the maximum desired 386 to 819 819 N⋅m
Desired Torque torque of pump 2 at ATT mode, “BRK2”
Breaker 3 Pump 2 Max. The valve to control the maximum desired 386 to 819 819 N⋅m
Desired Torque torque of pump 2 at ATT mode, “BRK3”
Breaker 4 Pump 2 Max. The valve to control the maximum desired 386 to 819 819 N⋅m
Desired Torque torque of pump 2 at ATT mode, “BRK4”

T5-1-25
 TROUBLESHOOTING / General
Correspondence Chart between Hexadecimal Number
and Binary Number
Hexadecimal
Number
0 1 2 3 4 5 6 7 8 9 A b C d E F
Binary Number 0000 0001 0010 0011 0100 0101 0110 0111 1000 1001 1010 1011 1100 1101 1110 1111

(Ex.) Monitor Display

60 Hexadecimal Number 2 Digits Display Section

Upper Lower

1. Convert the upper and lower number on the

hexadecimal number 2 digits display section.
(Refer to Correspondence Chart between Hexa-
decimal Number and Binary Number.)
Upper 6 0110
Lower 0 0000
Therefore, binary number 01100000 can be ob-
tained.

2. This value corresponds the bit on the Binary

Number Bit List (refer to T5-1-27).
If the valve is “1”, the operation at the bit corre-
sponds to the purpose.

bit6 ⇔ 1 Arm Digging Operation

bit5 ⇔ 1 Auxiliary 1
From these information arm digging operation
and auxiliary 1 correspond to the purpose.

T5-1-26
 TROUBLESHOOTING / General
BINARY NUMBER BIT LIST
Upper Lower
Hexadecimal
Number

Binary
Number

bit 7 bit 6 bit 5 bit 4 bit 3 bit 2 bit 1 bit 0

bit: Explanation
bit7: Boom Raise Operation
bit6: Arm Digging Operation
bit5: Auxiliary 1
bit4: Swing Operation
bit3: Travel Operation
bit2: Attachment Operation
bit1: Swing ⋅ Front Attachment
bit0: Auxiliary 2

T5-1-27
 TROUBLESHOOTING / General
(Blank)

T5-1-28
 TROUBLESHOOTING / Component Layout
MAIN COMPONENT LAYOUT

3 4

7
8
9
1 10
11
12

13

23

14
22
15
21
20 16
19 T16J-01-01-007
18
17

1 - Bucket 7 - Swing Bearing 13 - Radiator / Oil Cooler / 19 - Pump Drain Filter

Air Condenser
2- Bucket Cylinder 8- Center Joint 14 - Engine 20 - Signal Control Valve
3- Arm 9- Swing Device 15 - Oil Filter 21 - Hydraulic Tank
4- Arm Cylinder 10 - Fuel Tank 16 - Pilot Filter 22 - Travel Pilot Valve
5- Boom 11 - Solenoid Valve Unit 17 - Pump Device 23 - Front Attachment / Swing
Pilot Valve
6 - Boom Cylinder 12 - Control Valve 18 - Travel Device

T5-2-1
 TROUBLESHOOTING / Component Layout
ELECTRICAL COMPONENT LAYOUT
(Overview)

• Pressure Sensor (Swing ⋅ Front Attachment)

Refer to swing device group.
1
8
9
2 3 4 5 6 7 10
21 11
12

20

19
13

14

18

•N Sensor
•Engine Oil Pressure Switch
•Oil Level Sensor
17 15 •Coolant Temperature Sensor
•Overheat Switch (95 °C)
•Pressure Sensor (Swing) •Overheat Switch (105 °C)
•Pressure Sensor (Travel) •Coolant Temperature Switch
•4-Spool Pressure Sensor (QOS)
•5-Spool Pressure Sensor Refer to engine device.
16
Refer to signal control valve group.
• Pressure Sensor (Arm Roll-In) • Pump 1 ⋅ 2 Displacement Angle Sensor
T16J-01-01-009
• Pressure Sensor (Boom Raise) • Pump 1 ⋅ 2 Delivery Pressure Sensor
Refer to control valve group. • Pump 1 ⋅ 2 Control Proportional
Solenoid Valve
Refer to pump device group.

1 - Work Light (Boom) 7 - Outside Temperature 12 - Glow Plug 17 - Hydraulic Temperature

Sensor Sensor
2- Horn 8 - Fusible Link (45 A) 13 - Battery 18 - Washer Motor
3- Work Light 9 - Fusible Link (75 A) 14 - Alternator 19 - Monitor
4- Fuel Sensor 10 - Safety Relay 15 - Starter 20 - Wiper Motor
5- Solenoid Valve Unit 11 - Battery Relay 16 - EC Motor 21 - Work Light
6- Air Cleaner Restriction
Switch

T5-2-2
 TROUBLESHOOTING / Component Layout
ELECTRICAL SYSTEM
(Relays and Related Equipment)
Rear Deck
9
8
7 10
6

11
2

12
13

4 14

T16J-01-02-001

24 19
23
18
26
22
17
25
16
21
15
20

T16J-01-01-010
1 - GPS ON/OFF Switch 8 - MC (Main Controller) 15 - Load Damp Relay (R1) 21 - Wiper Relay A (R7)
(Satellite Navigation System
Equipped Machines Only)
2 - Boom Mode Switch 9- GPS Controller (Optional) 16 - Washer Relay (R2) 22 - Wiper Relay B1 (R8)
3 - Auto-Lubrication Switch 10 - Fuse Box 17 - Work Light Relay 3 (R3) 23 - Wiper Relay B2 (R8)
4 - Precision Mode Switch 11 - Learning Switch 18 - Work Light Relay 2 (R3) 24 - Wiper Relay B3 (R9)
5 - Swing Alarm Deactivation 12 - Dr.EX Connector to MC 19 - Work Light Relay 1 (R5) 25 - Auto-Lubrication Normal
Switch (Optional) Rotation Relay (R11)
6 - QOS Controller 13 - Download Connector (Not 20 - Horn Relay (R6) 26 - Auto-Lubrication Reverse
Connected on GPS Rotation (R12)
Equipped Machines)
7 - ICX (Information Controller) 14 - Dr.EX Connector to ICX

T5-2-3
 TROUBLESHOOTING / Component Layout
ELECTRICAL SYSTEM
(Monitors and Switches)

1 2

22

21
23
20
3
19
24
18
4

17
25
5

16
26
15 6
14 7
8
13 27
12
11 9

T16J-01-01-011
10 T178-01-01-004

1 - Coolant Temperature 8 - Alternator Indicator 15 - Overheat Indicator 22 - Engine Control Dial

Gauge
2 - Fuel Gauge 9 - Coolant Level Indicator 16 - Trench Digging Mode 23 - Auto-Idle / Acceleration
Indicator Selector
3- Display Selection Switch 10 - Precision Mode Indicator 17 - Digging Mode Indicator 24 - Power Mode Switch
4- SET Switch 11 - Auto-Lubrication Indicator 18 - Attachment Mode Indicator 25 - Travel Mode Switch
5- Work Mode Switch 12 - Engine Oil Level Indicator 19 - Liquid Crystal Display 26 - Work Light Switch
6- Fuel Level Indicator 13 - Engine Oil Pressure 20 - Auto-Idle Indicator 27 - Wiper / Washer Switch
Indicator
7 - Air Filter Restriction Switch 14 - Preheat Indicator 21 - Auto-Acceleration Indicator

T5-2-4
 TROUBLESHOOTING / Component Layout
ENGINE

3
2

9 8

T16J-01-01-008
1 - N Sensor 4 - Oil Level Sensor 6 - Overheat Switch (95 °C) 8 - Coolant Temperature
Switch (QOS)
2 - Starter 5 - Coolant Temperature 7 - Alternator 9 - Overheat Switch (105 °C)
Sensor
3 - Engine Oil Pressure Switch

T5-2-5
 TROUBLESHOOTING / Component Layout
PUMP DEVICE

1 2
5

4 3

T16J-01-01-002 9 8
T16J-01-01-003

SWING DEVICE

10

11

T16J-03-02-001

1 - Pump 2 (5-Spool) 4 - Pump 2 Displacement 7 - Pump 1 Delivery Pressure 10 - Swing Relief Valve
Angle Sensor Sensor
2 - Pump 1 (4-Spool) 5 - Pump 2 Control Solenoid 8 - Pump 1 Control Solenoid 11 - Pressure Sensor
Valve Valve (Swing ⋅ Front Attachment)
3 - Pump 1 Displacement 6 - Pump 2 Delivery Pressure 9 - Pilot Pump
Angle Sensor Sensor

T5-2-6
 TROUBLESHOOTING / Component Layout
CONTROL VALVE
Machine
Front
1

Right Block
(4-Spool)

9
8 Left Block 5
(5-Spool)
4
Machine
7 Front
3
Right Block
(4-Spool)
T16J-03-03-003
6
T16J-03-03-002
Left Block
(5-Spool)

SIGNAL CONTROL VALVE

12

11

13
Machine
10 Front

Control Valve Lower Side T16J-05-02-002

14

15
T16J-01-01-005

1 - Arm Regenerative Valve 5 - Overload Relief Valve 9 - Overload Relief Valve 13 - Pressure Sensor (Travel)
(Boom Mode) (Boom)
2 - Boom Overload Relief 6 - Main Relief Valve 10 - Pressure Sensor 14 - Pump Control Pressure
Selector Valve (Arm Roll-In) Sensor (5-Spool: SB)
3 - Overload Relief Valve 7 - Holding Valve Shift Valve 11 - Pressure Sensor 15 - Pump Control Pressure
(Arm) (Boom) (Boom Raise) Sensor (4-Spool: SA)
4 - Holding Valve Shift Valve 8 - Overload Relief Valve 12 - Pressure Sensor (Swing)
(Arm) (Bucket)

T5-2-7
 TROUBLESHOOTING / Component Layout
SOLENOID VALVE UNIT TRAVEL DEVICE

1 6 7
2
3
4

T183-01-02-012

T16J-05-02-001

1 - Solenoid Valve Unit (SC) 3 - Solenoid Valve Unit (SA) 5 - Solenoid Valve 7 - Travel Relief Valve
(Swing Preference Circuit)
2 - Solenoid Valve Unit (SB) 4 - Pilot Relief Valve 6 - Check Valve 8 - Counterbalance Valve

T5-2-8
 TROUBLESHOOTING / Component Layout
(Blank)

T5-2-9
 TROUBLESHOOTING / Component Layout
COMPONENTS IN CONTROL VALVE
1 2 3 4 5 6 7 8 9 10 11 12

Swing

39
Arm 1 13

38 Arm 2

37 Boom 2

14

36 Boom 1 15

35 16
Bucket 17
Aux. 18
34 19
20

Travel (R) 21
Travel
(L) 22
33

T16J-03-03-004

32 31 30 29 28 27 26 25 24 23
1 - Holding Valve Shift Valve 11 - Load Check Valve 21 - Overload Relief Valve 31 - Shuttle Valve
(Boom) (Arm 1 Tandem Circuit) (Aux.)
2 - Bypass Shut-Out Valve 12 - Holding Valve Shift 22 - Load Check Valve 32 - Main Relief Valve
Valve (Arm) (Left Travel Tandem Circuit)
3 - Load Check Valve 13 - Overload Relief Valve 23 - Bypass Shut-Out Valve 33 - Load Check Valve
(Arm 2 Tandem Circuit) (Arm) (Bucket Tandem Circuit)
4 - Load Check Valve 14 - Holding Valve Check 24 - Load Check Valve 34 - Overload Relief Valve
(Arm 2 Parallel Circuit) Valve (Arm) (Left Travel Parallel Circuit) (Bucket)
5 - Check Valve 15 - Load Check Valve 25 - Check Valve 35 - Load Check Valve
(Arm Flow Combining (Boom 2 Tandem (Bucket Flow Combining (Boom 1 Parallel
Circuit) Circuit) Circuit) Circuit)
6 - Check Valve 16 - Load Check Valve 26 - Check Valve 36 - Overload Relief Valve
(Aux. Flow Combining (Boom 2 Parallel (Main Relief Pressure (Boom)
Circuit) Circuit) Combining Circuit)
7 - Arm Regenerative Valve 17 - Overload Relief Valve 27 - Check Valve 37 - Check Valve
(Boom Mode) (Bucket Flow Combining (Boom Flow Combining
Circuit) Circuit)
8 - Check Valve 18 - Boom Overload Relief 28 - Flow Combiner Valve 38 - Holding Valve Check
(Arm 1 (Roll-Out) Parallel Selector Valve Valve (Boom)
Circuit)
9 - Load Check Valve 19 - Load Check Valve 29 - Check Valve 39 - Make-Up Valve (Arm 2)
(Arm 1 (Roll-In) Parallel Circuit) (Aux. Tandem Circuit) (Flow Combiner Valve Circuit)
10 - Load Check Valve 20 - Load Check Valve 30 - Check Valve
(Swing Tandem Circuit) (Aux. Parallel Circuit) (Main Relief Pressure
Combining Circuit)

T5-2-10
 TROUBLESHOOTING / Component Layout

13 14 17,18 21 Cross Section A

F E D C B A 31 32

30

Front Side

23

32

31

36 34
29 28 T16J-03-03-006
T16J-03-03-005
38
Cross Section B Cross Section C
40 41 44 46

Right Travel Left Travel Bucket Aux.

21
34 25 27

19
22

33

20
24

34

T16J-03-03-008 45 6 47 21
42 43
T16J-03-03-007

40 - Right Travel Forward Port 43 - Right Travel Reverse Port 45 - Bucket (Roll-In) Port 47 - Aux. Port
41 - Left Travel Forward Port 44 - Bucket (Roll-Out) Port 46 - Aux. Port
42 - Left Travel Reverse Port

T5-2-11
 TROUBLESHOOTING / Component Layout

1 2 3 4 5 6 7 8 9 10 11 12

Swing

39
Arm 1 13

38 Arm 2

37 Boom 2

14

36 Boom 1 15

35 16
Bucket 17
Aux. 18
34 19
20

Travel (R) 21
Travel
(L) 22
33

T16J-03-03-004

32 31 30 29 28 27 26 25 24 23
1 - Holding Valve Shift Valve 11 - Load Check Valve 21 - Overload Relief Valve 31 - Shuttle Valve
(Boom) (Arm 1 Tandem Circuit) (Aux.)
2 - Bypass Shut-Out Valve 12 - Holding Valve Shift Valve 22 - Load Check Valve 32 - Main Relief Valve
(Arm) (Left Travel Tandem
Circuit)
3 - Load Check Valve 13 - Overload Relief Valve 23 - Bypass Shut-Out Valve 33 - Load Check Valve
(Arm 2 Tandem Circuit) (Arm) (Bucket Tandem Circuit)
4 - Load Check Valve 14 - Holding Valve Check Valve 24 - Load Check Valve 34 - Overload Relief Valve
(Arm 2 Parallel Circuit) (Arm) (Left Travel Parallel Circuit) (Bucket)
5 - Check Valve 15 - Load Check Valve 25 - Check Valve 35 - Load Check Valve
(Arm Flow Combining (Boom 2 Tandem Circuit) (Bucket Flow Combining (Boom 1 Parallel Circuit)
Circuit) Circuit)
6 - Check Valve 16 - Load Check Valve 26 - Check Valve 36 - Overload Relief Valve
(Aux. Flow Combining (Boom 2 Parallel Circuit) (Main Relief Pressure (Boom)
Circuit) Combining Circuit)
7 - Arm Regenerative Valve 17 - Overload Relief Valve 27 - Check Valve 37 - Check Valve
(Boom Mode) (Bucket Flow Combining (Boom Flow Combining
Circuit) Circuit)
8 - Check Valve 18 - Boom Overload Relief 28 - Flow Combiner Valve 38 - Holding Valve Check Valve
(Arm 1 (Roll-Out) Parallel Selector Valve (Boom)
Circuit)
9 - Load Check Valve 19 - Load Check Valve 29 - Check Valve 39 - Make-Up Valve (Arm 2)
(Arm 1 (Roll-In) Parallel (Aux. Tandem Circuit) (Flow Combiner Valve
Circuit) Circuit)
10 - Load Check Valve 20 - Load Check Valve 30 - Check Valve
(Swing Tandem Circuit) (Aux. Parallel Circuit) (Main Relief Pressure
Combining Circuit)

T5-2-12
 TROUBLESHOOTING / Component Layout
Cross Section D Cross Section E
49 52 5 7 53
48

Boom 1 Boom 2 Arm 2 Arm 1

14
12
17
36
18

15
35
16

9
4
11
3

13
1 38 37 51 36
T16J-03-03-009
T16J-03-03-010
50 54 55
56

Cross Section F
Swing

13

A A
10

26

T16J-03-03-011
39 57

A-A T16J-03-03-019
22 24

48 - Boom 1 (Lower) Port 51 - Boom 2 (Raise) Port 54 - Arm 2 (Roll-In) Port 56 - Swing (Left) Port
49 - Boom 2 (Lower) Port 52 - Arm 2 (Roll-Out) Port 55 - Arm 1 (Roll-In) Port 57 - Swing (Right) Port
50 - Boom 1 (Raise) Port 53 - Arm 1 (Roll-Out) Port

T5-2-13
 TROUBLESHOOTING / Component Layout
SIGNAL CONTROL VALVE PORT
LOCATION
Pilot Valve Side(ISO PATTERN)
Port Name Connecting to Note
Port A Right Pilot Valve Boom Raise Pilot Pressure
Port B Right Pilot Valve Boom Lower Pilot Pressure
Port C Left Pilot Valve Right Swing Pilot Pressure
Port D Left Pilot Valve Left Swing Pilot Pressure
Port E Left Pilot Valve Arm Roll-Out Pilot Pressure
Port F Left Pilot Valve Arm Roll-In Pilot Pressure
Port G Right Pilot Valve Bucket Roll-In Pilot Pressure
Port H Right Pilot Valve Bucket Roll-Out Pilot Pressure
Port I Travel Pilot Valve Left Travel Forward Pilot Pressure
Port J Travel Pilot Valve Left Travel Reverse Pilot Pressure
Port K Travel Pilot Valve Right Travel Forward Pilot Pressure
Port L Travel Pilot Valve Right Travel Reverse Pilot Pressure
Port M Auxiliary Pilot Valve Auxiliary Open Pilot Pressure
Port N Auxiliary Pilot Valve Auxiliary Close Pilot Pressure
Port SA Pump Control Pressure Sensor (4-spool) Pump 1 Flow Rate Control
Port SB Pump Control Pressure Sensor (5-spool) Pump 2 Flow Rate Control
Port PI Pilot Shut-Off Valve Primary Pilot Pressure
Port PH Pilot Shut-Off Valve Primary Pilot Pressure (Heating Circuit)
Port SH Swing Parking Brake Brake Release Pressure
Port DF Hydraulic Oil Tank Returning to Hydraulic Oil Tank

Pilot Valve Side(HITACHI PATTERN)

Port Name Connecting to Note
Port A Right Pilot Valve Boom Raise Pilot Pressure
Port B Right Pilot Valve Boom Lower Pilot Pressure
Port C Left Pilot Valve Arm Roll-Out Pilot Pressure
Port D Left Pilot Valve Arm Roll-In Pilot Pressure
Port E Left Pilot Valve Left Swing Pilot Pressure
Port F Left Pilot Valve Right Swing Pilot Pressure
Port G Right Pilot Valve Bucket Roll-In Pilot Pressure
Port H Right Pilot Valve Bucket Roll-Out Pilot Pressure
Port I Travel Pilot Valve Left Travel Reverse Pilot Pressure
Port J Travel Pilot Valve Left Travel Forward Pilot Pressure
Port K Travel Pilot Valve Right Travel Forward Pilot Pressure
Port L Travel Pilot Valve Right Travel Reverse Pilot Pressure
Port M Auxiliary Pilot Valve Auxiliary Open Pilot Pressure
Port N Auxiliary Pilot Valve Auxiliary Close Pilot Pressure
Port SA Pump Control Pressure Sensor (4-spool) Pump 1 Flow Rate Control
Port SB Pump Control Pressure Sensor (5-spool) Pump 2 Flow Rate Control
Port PI Pilot Shut-Off Valve Primary Pilot Pressure
Port PH Pilot Shut-Off Valve Primary Pilot Pressure (Heating Circuit)
Port SH Swing Parking Brake Brake Release Pressure
Port DF Hydraulic Oil Tank Returning to Hydraulic Oil Tank

T5-2-14
 TROUBLESHOOTING / Component Layout

Pilot Valve Side

PH
C
A

E
M
D
H
B
F
SB
PI G

Pilot Valve
Side

K N

I
SH
J

DF

SA L
T178-03-06-016

T5-2-15
 TROUBLESHOOTING / Component Layout

Control Valve Side

Port Name Connecting to Note
Port 1 Control Valve Boom Raise Pilot Pressure
Port 2 Control Valve Bucket Roll-Out Pilot Pressure
Port 3 Control Valve Arm Roll-Out Pilot Pressure
Port 4  Plug
Port 5 Control Valve Left Swing Pilot Pressure
Port 6 Control Valve Right Swing Pilot Pressure
Port 7 Control Valve Bucket Roll-In Pilot Pressure
Port 8 Control Valve Bucket Roll-In Pilot Pressure
Port 9 Control Valve Left Travel Forward Pilot Pressure
Port 10 Control Valve Left Travel Reverse Pilot Pressure
Port 11 Control Valve Right Travel Forward Pilot Pressure
Port 12 Control Valve Right Travel Reverse Pilot Pressure
Port 13  Plug
Port 14  Plug
Port SE  Plug
Port SM Hydraulic Oil Tank Returning to Hydraulic Oil Tank
Port SN  Plug
Port SP Hydraulic Oil Tank Returning to Hydraulic Oil Tank
Port SL Control Valve Flow Combiner Valve Control Pressure
Port SK  Plug

T5-2-16
 TROUBLESHOOTING / Component Layout

Control Valve Side

SM
3

1 5

13
2 4
SK
SE
Pressure Sensor 8
(S3: Swing)

14
Control Valve 7
Side
9
6
10

SN
SL
11

Pressure Sensor (TR: Travel) 12 SP T16J-03-06-001

T5-2-17
 TROUBLESHOOTING / Component Layout
(Blank)

T5-2-18
 TROUBLESHOOTING / Troubleshooting A
TROUBLESHOOTING A PROCEDURE
Refer to troubleshooting A procedure in case any fault
codes are displayed after diagnosing the main con-
troller (MC) using Dr. EX (or the built-in diagnosing
system).

• How to Read Troubleshooting Flow Charts

YES(OK)
(2)
After completing the checking and/or measuring procedures in box (1),
・ (1) select YES (OK) or NO (NOT OK) and proceed to box (2) or (3).
(3)
NO(NOT OK)

Instructions, reference, and/or inspection methods and/or measurements are occasionally

・
described under the box. If incorrectly checked or measured, not only will troubleshooting
· Key switch: ON be unsuccessful but also damage to the components may result.

・ Refer to “Electrical System Inspection” Group (Group 6) for descriptions in the dotted-line
box.

・ Use Dr. EX (or the built-in diagnosing system) for descriptions in the double-line box.

・ Causes of machine problems are stated in the thick-line box. Scanning quickly through the
thick-line boxes allows you to estimate the possible causes before actually following the
flow chart.

NOTE: All harness end connectors are seen from

the open end side.

Harness

Open End
Side
Harness End Connector

T158-05-03-001

T5-3-1
 TROUBLESHOOTING / Troubleshooting A
FAULT CODE LIST

Fault Code Trouble Cause

01 Abnormal EEPROM • Faulty MC
02 Abnormal RAM
03 Abnormal A/D Conversion
04 Abnormal Sensor Voltage • Faulty MC
• Faulty Sensor
05 Abnormal N Sensor • Faulty N Sensor
06 Abnormal EC Sensor • Faulty MC
• Faulty Harness
• Faulty EC Sensor
07 Abnormal Engine Control Dial Angle • Faulty MC
• Faulty Harness
• Faulty Engine Control Dial
08 Abnormal Pump 1 Displacement Angle • Faulty MC
09 Abnormal Pump 2 Displacement Angle • Faulty Harness
• Faulty Pump Displacement Angle Sensor
10 Abnormal Pump 1 Delivery Pressure • Faulty MC
11 Abnormal Pump 2 Delivery Pressure • Faulty Harness
• Faulty Pump Delivery Pressure Sensor
12 Abnormal Pump 1 Pump Control Pressure • Faulty MC
13 Abnormal Pump 2 Pump Control Pressure • Faulty Harness
• Faulty Pump Control Pressure Sensor
14 Abnormal Swing Pilot Pressure • Faulty MC
15 Abnormal Boom Raise Pilot Pressure • Faulty Harness
16 Abnormal Arm Roll-In Pilot Pressure • Faulty Pilot Pressure Sensor
18 Abnormal Travel Pilot Pressure
19 Abnormal Hydraulic Oil Temperature • Faulty MC
• Faulty Harness
• Faulty Hydraulic Oil Temperature Sensor
20 Pump1 Control Malfunction • Faulty MC
21 Pump2 Control Malfunction • Faulty Harness
• Faulty Pump Control Solenoid Valve
• Faulty Pump Displacement Angle Sensor

T5-3-2
 TROUBLESHOOTING / Troubleshooting A
FAULT CODE 01 (ABNORMAL EEPROM)
FAULT CODE 02 (ABNORMAL RAM)
FAULT CODE 03
(ABNORMAL A/D CONVERSION)

• Check for loose harness connections beforehand.

YES * Faulty MC.

Check if engine and machine

actuators operate normally.
Faulty MC.
NO
· Refer to T4-6-2.
* Even if any fault codes are still displayed after re-
trying, as long as the engine and machine operate
normally, the machine can be operated as it is.

FAULT CODE 04
(ABNORMAL SENSOR VOLTAGE)
• Check for loose harness connections beforehand.
NO Faulty MC.

Check if fault code 06, 07, 08,

09, 10, 11, 12, 13, 14, 15, 16, · Refer to T4-6-2.
18, 19, 20 or 21 is displayed.
Faulty sensor or short circuited
harness between MC and
YES sensor.

FAULT CODE 05
(ABNORMAL N SENSOR)

• Check for loose harness connections beforehand.

• Fault code 05 is displayed when the engine speed
-1
is more than 4000 min .
• Even if signals from N sensor are not delivered
due to broken circuit or poor sensor installation,
few changes in operational performance occur,
making troubleshooting difficult. Use monitor
function.
YES Faulty MC.
Disconnect N sensor. Check if
resistance between sensor · Refer to T4-6-2.
side connector terminals is
2.3±0.2 kΩ (25 °C). Faulty N sensor.
NO

T5-3-3
 TROUBLESHOOTING / Troubleshooting A
FAULT CODE 06
(ABNORMAL EC SENSOR) YES Faulty harness be-
Check harness be-
tween MC and EC
tween MC connector
• Check for loose harness connections beforehand. YES C (31P) terminal #18
sensor.
and EC sensor termi-
nal #2 for breakage or
short circuit. Faulty MC.
Disconnect EC sen- NO
sor. Check if voltage
Disconnect EC sensor. YES between harness end · Refer to T4-6-2.
Check if resistance be- connectors #1 and #3
tween sensor side is 5±0.5 V. Check if voltage be- YES Broken harness be-
tween MC and EC
connector terminals #1 tween EC sensor
· Key switch: ON sensor terminal #3.
and #3 is less than harness end connec-
2.0±0.4 kΩ. Connect test tor terminal #1 and
harness between EC NO vehicle frame
sensor and base ma- Broken harness be-
matches specification.
chine side harness. tween MC and EC
· Key switch: ON NO sensor terminal #1.
Check if voltage changes
in accordance with speci- · Specification: 5±0.5 V
fications when engine
control dial is rotated. Faulty EC sensor.
· Test Harness: ST 7129 NO
· Specification: See table be- · Refer to T4-6-2.
low.

EC Sensor Specification
Minimum Speed 2.5 to 2.7 V
Maximum Speed (HP 3.3 to 3.7 V
Mode Switch: OFF)
Maximum Speed (HP Voltage at Maximum Speed
Mode Switch: ON) (HP Mode Switch: OFF) plus
0.2 V or more

Connector (Harness End Connector Viewed from the Open End Side)

MC Connector C

C1 C10

C23 C31
#18
EC Sensor

1 2 3

T5-3-4
 TROUBLESHOOTING / Troubleshooting A
FAULT CODE 07
(ABNORMAL ENGINE CONTROL DIAL
ANGLE) Faulty harness be-
Check harness be- YES
tween MC connector C tween MC and engine
• Check for loose harness connections beforehand. (31P) harness end ter- control dial.
YES minal #6 and switch
panel terminal #3 for
breakage or short cir- Faulty MC.
Disconnect switch cuit.
NO
panel. Check if voltage · Refer to T4-6-2.
YES between harness end
Disconnect switch panel. connector terminals #2 Broken harness be-
Check if resistance be- and #4 is 5±0.5 V. YES tween MC and engine
Check if voltage be-
tween switch panel side control dial terminal
· Key switch: ON tween switch panel
connector terminals #2 and #4.
harness end connec-
#4 is 5±0.5 kΩ. tor terminal #2 and
Reconnect switch panel. NO Broken harness be-
vehicle frame
Insert tester probe into tween MC and engine
matches specification.
connector terminal #3 from NO control dial terminal
the reverse side. Check if · Key switch: ON #2.
voltage varies as specified · Specification: 5±0.5 V
when engine control dial is
turned. Faulty engine control
NO dial.
· Specification: See table
below.

Engine Control Dial Specification

Minimum Speed 0.3 to 1.0 V
Maximum Speed 4.0 to 4.7 V

Connector (Harness End Connector Viewed from the Open End Side)

MC Connector C

#6
C1 C10

C23 C31

Switch Panel

#4 #2

T5-3-5
 TROUBLESHOOTING / Troubleshooting A
FAULT CODE 08
(ABNORMAL PUMP 1 DISPLACEMENT
ANGLE)
FAULT CODE 09
(ABNORMAL PUMP 2 DISPLACEMENT
ANGLE)

• Check for loose harness connections beforehand.

• Both pump 1 and pump 2 displacement angle
sensors (A-sensor) seldom fail at the same time.
Accordingly, if both fault codes 08 and 09 are dis-
played simultaneously, faulty harness may be the
cause of this problem. Faulty harness be-
Check harness be-
tween MC connector C YES tween MC and pump
(31P) harness end ter- displacement angle
sensor.
YES minal #2 (pump 1) or #5
(pump 2) and pump
displacement angle
Faulty MC.
Disconnect pump dis- sensor terminal #2 for
placement angle breakage or short cir- NO
NO sensor. Check if voltage cuit. · Refer to T4-6-2.
between harness end
connector terminals #1 Broken harness be-
and #3 is 5±0.5 V. Check if voltage be- YES tween MC and pump
tween pump displacement angle
Check if fault codes are displacement angle
· Key switch: ON sensor terminal #3.
switched after switching sensor harness end
pump 1 displacement NO connector terminal #1
angle sensor with pump Broken harness be-
and vehicle frame tween MC and pump
2 displacement angle matches specification.
sensor and retrying. NO displacement angle
· Key switch: ON sensor terminal #1.
· Specification: 5±0.5 V
Faulty pump dis-
YES placement angle
sensor.

Connector (Harness End Connector Viewed from the Open End Side)

MC Connector C
#2 #5
C1 C10

C23 C31

Pump Displacement Angle Sensor

1 2 3

T5-3-6
 TROUBLESHOOTING / Troubleshooting A
FAULT CODE 10
(ABNORMAL PUMP 1 DELIVERY PRES-
SURE)
FAULT CODE 11
(ABNORMAL PUMP 2 DELIVERY PRES-
SURE)

• Check for loose harness connections beforehand.

• Both pump 1 and pump 2 delivery pressure sen-
sors seldom fail at the same time. Accordingly, if
both fault codes 10 and 11 are displayed simulta-
neously, faulty harness may be the cause of this
problem. Faulty harness be-
Check harness be-
YES tween MC and pump
tween MC connector C
delivery pressure
(31P) harness end ter-
sensor
YES minal #1 (pump 1) or #4
(pump 2) and pump de-
livery pressure sensor
Faulty MC.
Disconnect pump de- terminal #2 for break-
livery pressure sensor. age or short circuit. NO
NO Check if voltage be- · Refer to T4-6-2.
tween harness end
connector terminals #1 Broken harness be-
and #3 is 5±0.5 V. Check if voltage be- YES tween MC and pump
tween pump delivery delivery pressure
Check if fault codes are pressure sensor har-
· Key switch: ON sensor terminal #3.
switched after switching ness end connector
pump 1 delivery pressure NO terminal #1 and vehi-
sensor with pump 2 de- Broken harness be-
cle frame matches tween MC and pump
livery pressure sensor specification.
and retrying. NO delivery pressure
· Key switch: ON sensor terminal #1.
· Specification: 5±0.5 V
Faulty pump delivery
YES pressure sensor.

Connector (Harness End Connector Viewed from the Open End Side)

MC Connector C
#1 #4
C1 C10

C23 C31

Pump Delivery Pressure Sensor

3 2 1

T5-3-7
 TROUBLESHOOTING / Troubleshooting A
FAULT CODE 12
(ABNORMAL PUMP 1 CONTROL PRES-
SURE)
FAULT CODE 13
(ABNORMAL PUMP 2 CONTROL PRES-
SURE)

• Check for loose harness connections beforehand.

• Both pump control pressure sensors (4-spool
(SA) and 5-spool (SB)) seldom fail at the same
time. Accordingly, if both fault codes 12 and 13
are displayed simultaneously, faulty harness may
be the cause of this problem.

Faulty harness be-

Check harness be- tween MC and pump
tween MC connector C YES
control pressure sen-
(31P) harness end ter- sor (4-spool or
YES minal #7 (pump 1) or 5-spool).
#13 (pump 2) and
pump control pressure
Disconnect pump con- sensor (4-spool or Faulty MC.
trol pressure sensor 5-spool) terminal #2 for NO
(4-spool or 5-spool). breakage or short cir- · Refer to T4-6-2.
NO Check if voltage be-
cuit. Broken harness be-
tween harness end
connector terminals #1 tween MC and pump
Check if voltage be- YES
and #3 is 5±0.5 V. control sensor
Check if fault codes are tween pump control (4-spool or 5-spool)
switched after switching · Key switch: ON pressure sensor terminal #3.
pump control pressure (4-spool or 5-spool)
sensor (4-spool) with NO harness end connector Broken harness be-
pump control pressure terminal #1 and vehicle tween MC and pump
sensor (5-spool) and re- frame matches specifi- NO control pressure sen-
trying. cation. sor (4-spool or
· Key switch: ON 5-spool) terminal #1.
· Specification: 5±0.5 V
Faulty pump control
YES pressure sensor
(4-spool or 5-spool).

Connector (Harness End Connector Viewed from the Open End Side)

MC Connector C
#13 #7
C1 C10

C23 C31

Pressure Sensors (4-Spool and 5-Spool)

1 2 3

T5-3-8
 TROUBLESHOOTING / Troubleshooting A
FAULT CODE 14
(ABNORMAL SWING PILOT PRESSURE)
FAULT CODE 15
(ABNORMAL BOOM RAISE PILOT
PRESSURE)
FAULT CODE 16
(ABNORMAL ARM ROLL-IN PILOT
PRESSURE) Check harness be- Faulty harness be-
FAULT CODE 18 tween MC connector C
YES tween MC and
(ABNORMAL TRAVEL PILOT PRESSURE) (31P) harness end pressure sensor.
YES each corresponding
• Check for loose harness connections beforehand. terminal and pressure
sensor terminal #2 for
• All pressure sensors seldom fail at the same time.
breakage or short cir-
Faulty MC.
Accordingly, if fault codes 14, 15, 16, and 18 are cuit. NO
displayed simultaneously, faulty harness may be · Refer to T4-6-2.
Connector C Terminal:
the cause of this problem. #14: Pressure Sensor (Swing)
#17: Pressure Sensor
Disconnect pressure (Boom Raise)
sensor. Check if voltage #15: Pressure Sensor
NO between harness end
(Arm Roll-In)
connector terminals #1 #3: Pressure Sensor
and #3 is 5±0.5 V. (Travel)
· Key switch: ON
Broken harness be-
Check if fault code dis- tween MC and
appears after switching Check if voltage be- YES
pressure sensor ter-
pressure sensor with an- tween pressure
minal #3.
other pressure sensor sensor harness end
and retrying. connector terminal #1
NO and vehicle frame Broken harness be-
Fault Code: matches specification. tween MC and
14: Pressure Sensor (Swing) NO pressure sensor ter-
· Key switch: ON minal #1.
15: Pressure Sensor · Specification: 5±0.5 V
(Boom Raise)
16: Pressure Sensor
(Arm Roll-In) Faulty pressure sen-
18: Pressure Sensor YES sor.
(Travel)

Connector (Harness End Connector Viewed from the Open End Side)

MC Connector C
#3

C1 C10

C23 C31
#14 #15 #17

Pilot Pressure Sensor

1 2 3

T5-3-9
 TROUBLESHOOTING / Troubleshooting A
FAULT CODE 19
(ABNORMAL OIL TEMPERATURE)

• Check for loose harness connections beforehand.

Connect oil tempera-
YES Faulty MC.
ture sensor harness
end connector terminal
#1 to #2 with a clip. · Refer to T4-6-2.
Remove connector B
YES (25P) and connector C Connect MC connec- Broken harness be-
(31P) from MC. Check tor B (25P) harness YES tween MC and oil
for continuity between end terminal #22 to temperature sensor
connector B harness vehicle frame. Check terminal #1.
end terminal #22 and for continuity between
Disconnect oil tempera-
connector C terminal NO oil temperature sensor
ture sensor. Check if Broken harness be-
#24. harness end connec-
sensor side connector tween MC and oil
tor terminal #2 and
resistance matches NO temperature sensor
vehicle frame.
specification. terminal #2.
· Specification: See table
below.
Faulty oil temperature
NO sensor.

Oil Temperature Specification

Oil Temperature Resistance
(°C) (kΩ)
−20 16.2±1.6
0 (5.88)
20 2.45±0.24
40 (1.14)
60 (0.534)
80 0.322

Connector (Harness End Connector Viewed from the Open End Side)

MC Connector B
B1 B8

B19 B25
#22

MC Connector C

C1 C10

C23 C31
#24

Oil Temperature Sensor

1 2

T5-3-10
 TROUBLESHOOTING / Troubleshooting A
FAULT CODE 20
(ABNORMAL PUMP 1 SWASH ANGLE
CONTROL)
FAULT CODE 21
(ABNORMAL PUMP 2 SWASH ANGLE
CONTROL)

• Check for loose harness connections beforehand.

• Fault codes 20 and 21 indicate the target swash
angle disagrees with the real one when MC or-
ders the target swash angle is set.

The Case of Fault Code 20

OK Faulty MC or pump 1
Check resistance be- (4-spool).
MC side connector A, either YES tween connectors #1 and · Refer to T4-6-2.
#3 or #4 comes in contact #2 of pump control sole-
with the main frame with a noid valve (Pump 1).
clip. Check if the current Faulty pump control so-
· Normal value: NOT OK lenoid valve (Pump 1).
flows from connector #1 or 14±3 Ω (20 °C)
#2 on the harness side of
the pump control solenoid
valve (Pump 1). Faulty harness between
pump control solenoid
NO valve (Pump 1) and MC.

The Case of Fault Code 21

OK Faulty MC or pump 2
Check resistance be- (5-spool).
YES tween connectors #1 and
#2 of pump control sole-
MC side connector A, either
noid valve (Pump 2).
#19 or #20 comes in contact Faulty pump control so-
with the main frame with a · Normal value: NOT OK lenoid valve (Pump 2).
clip. 14±3 Ω (20 °C)
Check if the current flows
from connector #1 or sole-
noid valve (Pump 2). Faulty harness between
pump control solenoid
NO valve (Pump 2) and MC.

Connector(Harness End Connector Viewed from the

Open End Side)

MC: Connector A Pump Control

Solenoid Valve
#3 #4
A1 A11

1 2

A25 A32
#19 #20

T5-3-11
 TROUBLESHOOTING / Troubleshooting A
(Blank)

T5-3-12
 TROUBLESHOOTING / Troubleshooting B
TROUBLESHOOTING B PROCEDURE
Apply troubleshooting B procedure when no fault code
is displayed on the Dr.EX (or the built-in diagnosing
system) although the machine’s operation is
abnormal.
On the front section pages of this group T5-4, are
tables indicating the relationship between machine
trouble symptoms and related parts which may cause
such trouble if failed.
Start the troubleshooting with more probable causes
selected by referring to these tables.

• How to Read the Troubleshoting Flow Charts

YES(OK)
(2)
• After checking or measuring item (1), select either YES (OK) or
・ (1) NO (NOT OK) and proceed to item (2) or (3), as appropriate.

(3)
NO(NOT OK)

・ • Special instructions or reference item are indicated in the spaces under the box.
Incorrect measuring or checking methods will render troubleshooting impossible,
· Key switch: ON and may damage components as well.

• Explanation of how to use test harness kit required. Refer to “Electrical System
・
Inspection” Group (Group 6) in this section.

・ • Use Dr.EX (or the built-in diagnosing system) function.

・ • Causes are stated in a thick-line box. Scanning through thick-line boxes, possible
causes can be seen without going through the flow chart.

T5-4-1
 TROUBLESHOOTING / Troubleshooting B
RELATIONSHIP BETWEEN MACHINE
TROUBLE SYMPTOMS AND RELATED
PARTS
This table indicates the relationship between machine
trouble symptoms and the potential problem parts,
which may cause trouble if failed, and the evaluation
methods of these components.
Parts
EC Motor EC Sensor Engine Control Dial
• Moves governor. • Detects minimum governor • Indicates governor lever posi-
speed position (2.5 V) only tion (engine target speed).
when key switch is turned ON.
Function • Detects minimum and maxi-
mum speed position when
engine learning is conducted.
• Governor lever doesn’t move. • Engine speed is controlled • Engine speed doesn’t change
based on idle position set even if engine control dial is
Symptoms in control when key switch is turned ON. turned.
system when trouble Therefore, engine speed is • If discontinuity or short circuit
always controlled with error in occurs in engine control dial,
occurs. idle position setting if set in- target speed of 1400 min-1 is
correctly. used as back-up value.
• Even if engine control dial is • Error in setting will seldom • Engine speed is kept un-
turned, engine speed doesn’t occur so that change in ma- changed from 1400 min-1.
increase from slow idle speed. chine operation will not be no- (Auto-idle system functions.
• Engine start may be difficult ticed. Engine can be stopped by key
though starter rotates. • In case error is set on lower switch.)
• Engine will stall if discontinuity side, engine speed changes
occurs in EC motor while en- but runs slower than normal
gine is running at more than a through the full range when
specified speed. engine control dial is turned.
• Engine will become uncon- (Note: In case error is set on
trollable if discontinuity occurs upper side, EC motor is driven
Symptoms in ma- in EC motor while engine is so that it runs faster than the
chine operation when running at lower than a speci- control range. However, mo-
fied speed. Engine cannot be tor, a worm gear type, holds
trouble occurs. stopped with key switch. governor lever at maximum
constant position, preventing
engine stall. When engine
control dial is turned to mini-
mum speed position, governor
lever is returned to idle posi-
tion.)
• When starting engine, engine
speed fluctuates.
• Starting engine is occasionally
difficult.

By Fault Code  Fault code 06 is displayed. Fault code 07 is displayed.

Monitor Item: EC Angle (Dis- Monitor Item: Engine Target
played by built-in diagnosing Speed, Dial Angle (Displayed by
By Monitor system) built-in diagnosing system)

Function
Eval-
uation
• Install lamp harness (ST
Using Test 7125) to check EC output
signal and harness for any
 
Harness
abnormality.
Others   
• Engine is stopped by EC mo- • If EC sensor is faulty, engine
tor. (Engine stop motor is not learning is not performed.
NOTE provided.) 
Fuel cut-off cable is provided.

Descriptions of Con- T2-1 T2-1 T2-1

trol (Operational Prin-
ciple Section in T/M)

T5-4-2
 TROUBLESHOOTING / Troubleshooting B

Pump 1 Delivery Pump 2 Delivery Pressure Sensor Pressure Sensor

Pressure Sensor Pressure Sensor (Travel) (Swing, Front Attachment)
• Monitors pump delivery • Monitors pump delivery pres- • Monitors travel pilot pres- • Monitors swing and front
pressure to control HP mode, sure to control HP mode, E sure to control auto-idle, attachment pilot pressure to
E mode, auto-acceleration, mode, auto-acceleration, auto-acceleration, rising control auto-idle mode.
horsepower control, and horsepower control, swing pressure mode control.
swing horsepower reducing horsepower reducing control
control. and attachment mode control.
• If pump delivery pressure • If pump delivery pressure • No signals arrive to MC • No signals arrive to MC
sensor output is 0.25 V to sensor output is 0.25 V to
4.50 V, following symptoms 4.50 V, following symptoms
will be presented by back-up will be presented by back-up
mode function. mode function.

• HP mode is inoperable. • HP mode is inoperable. • Engine speed doesn’t in- • Engine speed doesn’t in-
• Auto-acceleration control is • Auto-acceleration control is crease even if crease even if any front at-
inoperable. inoperable. auto-idle/auto-acceleration tachment actuator and the
• Engine easily stalls. • Engine easily stalls. selector is auto-idle posi- swing are operated with
• Under swing combined op- tion. auto-idle/auto-acceleration
erations, swing power is • Engine speed doesn’t in- selector is auto-idle position.
weak. crease even if
auto-idle/auto-acceleration
selector is
auto-acceleration position.
• Travel power is weak.

Fault codes 10 is displayed. Fault codes 11 is displayed. Fault code 18 is displayed. 

Monitor Item: Pump 1 delivery Monitor Item: Pump 2 delivery Monitor Item: Travel Control Monitor Item: Swing, Front At-
pressure (Displayed by built-in pressure (Displayed by built-in Pilot Pressure (displayed tachment Operation (displayed
diagnosing system) diagnosing system) built-in diagnosing system). built-in diagnosing system).
Monitor pressure change Monitor pressure change while
while traveling machine. operating front attachment and
the swing.

   

   
• Judge if pressure sensor is • Judge if pressure sensor is
faulty or port is clogged by faulty or port is clogged by
  switching pressure sensor switching pressure sensor
with another pressure sen- with another pressure sen-
sor. sor.
T2-1 T2-1 T2-1 T2-1

T5-4-3
 TROUBLESHOOTING / Troubleshooting B

Parts Pressure Sensor Pressure Sensor

Pressure Sensor (Swing)
(Boom Raise) (Arm Roll-In)
• Monitors swing pilot pressure • Monitors boom raise pilot • Monitors arm roll-in pilot pres-
to control auto-acceleration, pressure to control HP mode, sure to control HP mode, and
swing horsepower reducing, and auto-acceleration. auto-acceleration.
swing preference, and swing
Function alarm.

Symptoms in control • No signals arrive to MC • No signals arrive to MC • No signals arrive to MC

system when trouble
occurs.
• Even if the swing is operated, • Even if boom is raised with • Even if arm is rolled-in with
the auto-acceleration switch HP mode switch ON, engine HP mode switch ON, engine
ON engine speed doesn’t in- speed doesn’t increase. speed doesn’t increase.
crease. • Even if boom is raised with • Even if arm is rolled-in with
• The front attachment has less auto-idle/auto-acceleration auto-idle/auto-acceleration
power under the swing/the selector is auto-acceleration selector is auto-acceleration
front combined operation. position, engine speed doesn’t position, engine speed doesn’t
• The swing alarm (optional) increase. increase.
doesn’t work.
Symptoms in machine
operation when trou-
ble occurs.

Fault code 14 is displayed. Fault Code 15 is displayed. Fault code 16 is displayed.

By Fault Code
Monitor Item: Swing Control Pilot Monitor Item: Boom Raise Pilot Monitor Item: Arm Roll-In Pilot
Pressure (displayed built-in di- Pressure (displayed built-in di- Pressure (displayed built-in di-
By Monitor agnosing system). agnosing system). agnosing system).
Function Monitor pressure change while Monitor pressure change while Monitor pressure change while
Eval- swinging upperstructure. raising boom. rolling arm in.
uation

Using Test
  
Harness

Others   
• Judge if pressure sensor is • Judge if pressure sensor is • Judge if pressure sensor is
faulty or port is clogged by faulty or port is clogged by faulty or port is clogged by
switching pressure sensor switching pressure sensor switching pressure sensor
with another pressure sensor. with another pressure sensor. with another pressure sensor.
NOTE

Descriptions of Con- T2-1 T2-1 T2-1

trol (Operational Prin-
ciple Section in T/M)

T5-4-4
 TROUBLESHOOTING / Troubleshooting B

Pressure Sensor Pump 1 Displacement Pump 2 Displacement

(Counterweight Removal ) N Sensor
(Optional) Angle Sensor Angle Sensor
• Monitors counterweight re- • Senses main hydraulic pump • Senses main hydraulic pump • Monitors engine speed to
moval pilot pressure to con- 1 displacement angle. 2 displacement angle. operate engine speed sens-
trol pump in counterweight ing control.
removal.

• No signals arrive to MC. • Loss of pump control. • Loss of pump control. • Speed sensing control is
inoperable.

• No pressure rise and no flow • Machine mistracks. (It may • Machine mistracks. (It may • Engine stalls under adverse
reduction even if moving be noticed when traveling be noticed when traveling operating conditions such as
control lever. straight.) straight.) at high altitude.
• Engine overload or decrease • Engine overload or decrease
in speed may result. in speed may result.

Fault code 08 or 20 is dis- Fault code 09 or 21 is dis- Fault code 05 is displayed.

 played. played. (When the Engine Speed more
than 4000 min-1)
Monitor Item: Counterweight Monitor Item: Pump 1 Actual Monitor Item: Pump 2 Actual Monitor Item: Actual engine
removal Displacement. displacement speed (If N sensor fails, engine
speed is not measured.)

   

   
• Judge if pressure sensor is • Judge if displacement angle • Judge if displacement angle • Even if signals from N sen-
faulty or port clogged by sensor is faulty or port sensor is faulty or port sor are not delivered due to
switching pressure sensor clogged by switching dis- clogged by switching dis- broken circuit or poor sensor
with another pressure sen- placement angle sensor with placement angle sensor with installation, few changes in
sor. another displacement sen- another displacement sen- operational performance
sor. sor. occur, making troubleshoot-
ing difficult. Use monitor
function.
T2-1 T2-1 T2-1 T2-1

T5-4-5
 TROUBLESHOOTING / Troubleshooting B

Parts Pump Control Pressure Pump Control Pressure Hydraulic Oil Temperature
Sensor (4-Spool) (SA) Sensor (5-Spool) (SB) Sensor
• Pressure Pi flows from pump • Pressure Pi flows from pump • Monitors hydraulic oil tem-
1 flow control valve to pump 2 flow control valve to pump perature to control
control pressure sensor control pressure sensor auto-warming up.
(4-spool), which sends the (5-spool), which sends the
Function signal of pressure Pi to MC. signal of pressure Pi to MC.

• Pump control pressure sen- • Pump control pressure sen- • If circuit breakage occurs,
Symptoms in control sor (4-spool) doesn’t send sor (5-spool) doesn’t send system operates as if hydrau-
the signal to MC. the signal to MC. lic oil temperature is 40 °C
system when trouble • Due to the backup mode the • Due to the backup mode the (Dr. EX or monitor will not in-
occurs. operations as below are operations as below are dicate 40 °C in diagnosis
done. done. operation).
• Pump 1 is kept at the maxi- • Pump 2 is kept at the maxi- • Even if oil temperature is
mum swash angle regardless mum swash angle regard- lower than 0 °C,
of the control lever stroke. less of the control lever auto-warming up control
• The engine stalls easily. stroke. doesn’t operate so that en-
• The engine stalls easily. gine runs at idle speed when
engine is started.

Symptoms in machine
operation when trou-
ble occurs.

Failure code 12 is displayed. Failure code 13 is displayed. Fault code 19 is displayed.

By Fault Code

By Monitor Monitor Item: Pump 1 Pump Monitor Item: Pump 2 Pump Monitor Item: Hydraulic Oil Tem-
Control Pressure Control Pressure perature
Function

Eval-
uation

Using Test
  
Harness

Others   

NOTE   

Descriptions of Con- T2-1 T2-1 T2-1

trol (Operational Prin-
ciple Section in T/M)

T5-4-6
 TROUBLESHOOTING / Troubleshooting B

Solenoid Valve
Solenoid Valve Unit (SA) Solenoid Valve Unit (SB) Solenoid Valve Unit (SC)
(Swing Preference Circuit)
• Temporarily increases main • Shifts travel motor dis- • Controls boom mode selec- • Changes the pilot circuit of
relief valve set-pressure placement angle. tor. Boom overload relief swing and boom raise.
when operating machine ei- pressure decrease 11.8 MPa
ther in power digging, travel (120 kgf/cm2) @110 L/min.
operation and precision
mode.

• In case solenoid valve unit • Travel motor displacement • Boom overload relief pres- • Changing swing/boom raise
(SA) is not activated, pres- angle is fixed to the maxi- sure doesn’t decrease. circuit isn’t performed.
sure at port SA becomes 0 mum (slow speed).
MPa (0 kgf/cm2).

When the valve is kept close: • Travel speed mode does not • Even if the boom mode se- • When operating the swing,
• Relief pressure stays at shift to the fast speed mode lector switch is turned ON, boom raise, the swing is al-
normal 30.4 MPa (310 with the travel mode switch. vibration cannot be con- ways given priority.
kfg/cm2). Even if power dig- trolled at the boom lower. • When operating the
ging switch is pressed, relief swing⋅boom raise on trenching
pressure doesn’t increase. mode, the swing isn’t given
Power doesn’t increase. priority.

When the valve is kept open:

• Even if power digging switch
is pressed, relief pressure
increase.
Power increase.

   

Monitor Item: Power Boost Monitor Item: Travel motor Monitor Item: Boom mode se- Monitor Item: Swing priority se-
Control Pressure control selection pressure lection pressure lection Pressure

• Install lamp harness (ST • Install lamp harness (ST • Install lamp harness (ST
7130) to check output sig- 7130) to check output sig- 7130) to check output sig-
nals from MC and harness nals from MC and harness nals from MC and harness

condition. condition. condition.

   

   

T2-1 T2-1 T2-1 T2-1

T5-4-7
 TROUBLESHOOTING / Troubleshooting B

Parts Pump 1 Control Solenoid Pump 2 Control Solenoid

MC
Valve Valve
• Shift the pump 1 displacement • Shifts the pump 2 displace- • Controls engine, pump, and
angle. ment angle. valve operation.
Function

• Loss of pump 1 control. • Loss of pump 2 control. • Depending on trouble situa-

tions, control system malfunc-
tion may differ. (The following
Symptoms in control symptoms in machine opera-
tion indicates that MC logic
system when trouble circuit has failed.)
occurs.

• Pump 1 flow rate becomes • Pump 2 flow rate becomes • Even if key switch is turned
minimum if the harness or so- minimum if the harness or so- ON, step motor will not move
lenoid valve is broken. lenoid valve is broken. to the START position so that
engine cannot start. Even
though engine starts, speed
Symptoms in machine stays slow.
operation when trou- • Since pump displacement is
held at minimum, all actuator
ble occurs. speeds are slow.

Fault code 20 is displayed. Fault code 21 is displayed. Fault codes 01, 02, and 03 are
By Fault Code displayed. Other fault codes may
be displayed.
Monitor Item: Pump 1 Desired Monitor Item: Pump 2 Desired
By Monitor
Eval- Displacement Displacement 
uation
Function Pump 1 Actual Displacement Pump 2 Actual Displacement
Using Test   
Harness
Others   
• After switching one solenoid • After switching one solenoid • Before suspecting a failure in
valve harness with the other, it valve harness with the other, it MC, be sure to check the
is possible to check if the so- is possible to check if the so- fuses in control system. If any
lenoid valve is faulty or the lenoid valve is faulty or the sensor in 5 V system is
NOTE harness is off. harness is off. short-circuited, sensor fault
(Switch harness of pump deliv- (Switch harness of pump de- code 04 will be displayed.
ery pressure sensor and pump livery pressure sensor and
displacement angle sensor with pump displacement angle
the other.) sensor with the other.)
Descriptions of Con- T2-1 T2-1 T2-1
trol (Operational Prin-
ciple Section in T/M)

T5-4-8
 TROUBLESHOOTING / Troubleshooting B

Auto-Idle/Auto-Acceleration Auto-Idle/Auto-Accelerati
Power Digging Switch Travel Mode Selector on Selec-
Selector (Auto-Idle) tor(Auto-Acceleration)
• Activates power digging con- • Changes travel mode. • Activates auto-idle control. • Activates auto-acceleration
trol. Fast Mode: 0 V ON: 0 V → Auto-idle is op- control.
ON: 0 V→Increasing Pres- Slow Mode: 5 V erable. ON: 0 V → Auto-acceleration
sure OFF: 5 V → Inoperable is operable.
OFF: 5 V→ Not increasing . OFF: 5 V → Inoperable.
Pressure
• Broken Circuit: Pressure • Broken Circuit in Switch: • Broken Circuit: Auto-idle • Broken Circuit:
doesn’t increase. Travel speed remains un- system is inoperable. Auto-acceleration control is
• Short Circuit: Pressure in- changed in slow mode (5 V). • Short Circuit: Even if inoperable.
creases for 8 seconds after • Short Circuit in Switch: auto-idle/auto-acceleration • Short Circuit: Even if
turning key switch and stops Travel speed remains un- selector is OFF, auto-idle auto-idle/auto-acceleration
increasing. changed in fast mode (0 V). control is always performed. selector is OFF,
auto-acceleration control is
always performed.

• Power digging control • Even if travel mode selector • Same as described above. • Same as described above.
doesn’t operate if broken is turned to the FAST posi-
circuit or short circuit occurs. tion, fast travel mode cannot
be selected.
• Even if travel mode selector
is turned to the SLOW posi-
tion, slow travel mode can-
not be selected.

   
Monitor Item: Power Digging Monitor Item: Travel Mode Monitor Item: Monitor Item:
(Boost) Switch Switch Auto-Idle/Auto-Accel Switch Auto-Idle/Auto-Accel Switch

   
   

   

T2-1 T2-1 T2-1 T2-1

T5-4-9
 TROUBLESHOOTING / Troubleshooting B

Parts Power Mode Switch Power Mode Switch Power Mode Switch
(HP Mode) (E Mode) (P Mode)
• Activates HP mode control. • Selects E mode. • Select P mode.
ON: 0 V → HP mode is oper- ON: 0 V → E mode ON: 0 V
able. OFF: 5 V → Normal OFF: 0 V
OFF: 5 V → Inoperable. (If E mode and HP mode are
Function not selected, MC judges as P
mode is selected. )

• Broken Circuit: Even if HP • Broken Circuit: Even if E • Broken circuit: P mode.

mode is selected, HP mode is mode is selected, engine • Short circuit: E mode or HP
inoperable. speed doesn’t decrease. mode.
• Short Circuit: Even if HP • Short Circuit: Engine speed
mode switch is turned OFF, doesn’t increase to the
HP mode system is not deac- maximum. Auto-idle control is
Symptoms in control tivated. inoperable.
system when trouble
occurs.

• Same as described above. • Same as described above. • Same as described above.

Symptoms in machine
operation when trou-
ble occurs.

By Fault Code   

By Monitor Monitor Item: E/P/HP Mode Monitor Item: E/P/HP Mode Monitor Item: E/P/HP Mode
Eval- Switch Switch Switch
Function
uation Using Test   
Harness
Others   

NOTE   

Descriptions of Con- T2-1 T2-1 T2-1

trol (Operational Prin-
ciple Section in T/M)

T5-4-10
 TROUBLESHOOTING / Troubleshooting B

Work Mode Switch Work Mode Switch Attachment Select Switch Boom Mode
(Digging Mode) (Attachment Mode) (Optional) Selector Switch
• Allows normal control to be • Functions only when optional • Functions only when optional • Lowers overload relief pres-
performed. attachment kit is equipped. attachment kit is equipped. sure at the boom cylinder
• The upper limit of pump 2 • The upper limit of pump 2 rod side.
maximum flow is set low. maximum flow can be
changed at three stages.

• It’s unable to reduce the • The upper limit of pump 2 • Broken Circuit : Boom mode
upper limit of pump 2 maxi- maximum flow cannot be selector control is not per-
mum flow, which is as much changed at three stages. formed.
as that of digging mode. • The maximum flow is kept in • Short-Circuit: Overload relief
maximum flow at attachment pressure remains low con-
mode. stantly at the boom cylinder
rod side, and jack up is dis-
abled.
―

• Even if attachment mode is • Even if attachment mode is • Same as described above.

selected, the attachment selected and attachment
speed is as fast as that of select switch is changed, the
digging mode. breaker speed doesn’t
change.

   
Monitor Item: Work Mode Monitor Item: Work Mode Monitor Item: ATT Mode Monitor Item: Boom Mode Se-
lector Switch.

   

   

   

T2-1 T2-1 T2-1 T2-1

T5-4-11
 TROUBLESHOOTING / Troubleshooting B

Parts
Precision Mode Switch Engine Learning Switch Flow Combiner Valve
• Increases pressure and re- • Starts engine learning • Supplies hydraulic oil to both
duces pump flow rate. ON: 0 V → Learning right and left travel spools
OFF: 5 V → Normal Control from pump 1 during combined
operation of travel and
Function front/swing.

• Broken Circuit: Pressure • Engine learning is not per- • During combined operation of
doesn’t increase. formed. travel and front/swing, insuffi-
It’s unable to reduce the up- cient oil is supplied to left
per limit of pump maximum travel spool.
flow rate.
• Short Circuit: Precision mode
switch is OFF, precision mode
Symptoms in control is always performed
system when trouble Flow rate does’ t increase.
occurs.

• Same as described above. • Machine will operate normally • While traveling, when
problem is caused by broken front/swing lever is operated,
circuit or discontinuity of machine mistracks to the left.
switch. (Only learning cannot
Symptoms in machine be performed.)
operation when trou- • If short circuit occurs, learning
ble occurs. mode operation starts when
key switch is turned ON.
Therefore, engine will stall at
2 second or 20 seconds after
engine starts.
By Fault Code   
By Monitor Monitor Item: Precision Mode Monitor Item: Engine Learning
Switch. 
Eval- Function
uation Using Test   
Harness
Others   

NOTE   

Descriptions of Con- T2-1 T2-1 T3-3

trol (Operational Prin-
ciple Section in T/M)

T5-4-12
 TROUBLESHOOTING / Troubleshooting B

Pump 1 Flow Control Pump 2 Flow Control Bypass Shut-Out Valve Bypass Shut-Out Valve
Valve Valve (4-Spool Side) (5-Spool Side)
• Supplies flow rate control • Supplies flow rate control • Supplies pressure oil from • Supplies pressure oil from
pressure Pi to pump control pressure Pi to pump control pump 1 to auxiliary spool pump 2 to bucket 1 spool
pressure sensor (4-spool) in pressure sensor (5-spool) in when auxiliary spool is oper- when bucket digging is op-
response to lever stroke response to lever stroke ated. erated.
when boom (lower), bucket when boom (raise), arm (roll
(roll-out/in), or right travel, is out/in), swing (right/left), left
operated. travel, or auxiliary is oper-
ated.
• If spool is bound in the fully • If spool is bound in the fully • If spool is bound in the fully • If spool is bound in the fully
opened position, even if con- opened position, even if opened position, single at- opened position, single at-
trol lever is in neutral, pump control lever is in neutral, tachment operation speed tachment operation speed
1 swash angle is maximum. pump 2 swash angle is becomes slow. becomes slow.
(When traveling with travel maximum. (When traveling • If spool is bound in the fully • If spool is bound in the fully
levers held in half way with travel levers held in closed position, main relief closed position, main relief
stroke, machine mistracks to half way stroke, machine valve continues to relieve with valve continues to relieve
the left.) mistracks to the right.) all control levers positioned in with all control levers posi-
• If spool is bound in the fully • If spool is bound in the fully neutral. tioned in neutral.
closed position, even if con- closed position, even if con- • If spool is bound in opened • If spool is bound in opened
trol lever is operated, pump 1 trol lever is operated, pump position, when all control lev- position, when all control
swash angle is held to mini- 2 swash angle is held to ers are in neutral, pump 1 levers are in neutral, pump
mum. (Right travel is inop- minimum. (Left travel is in- pressure is higher than pump 2 pressure is higher than
erable in single travel opera- operable in single travel 2 pressure. pump 1 pressure.
tion. Bucket speed is very operation. Swing speed is
slow.) very slow.)

• Same as described above. • Same as described above. • Same as described above. • Same as described above.

   
Monitor Item: Pump 1 Flow Monitor Item: Pump 2 Flow
Control Pressure Control Pressure  

   

   

   

T3-6 T3-6 T3-3 T3-3

T5-4-13
 TROUBLESHOOTING / Troubleshooting B

Parts Flow Combiner Valve Swing Parking Brake

Arm Regenerative Valve
Control Spool Release Spool
• Supplies control pressure to • Supplies swing parking brake • If the pressure on arm cylin-
flow combiner valve when release pressure when shifted der rod side is high, return oil
shifted by right travel pilot by boom, arm, bucket, or from rod side flows to arm
pressure. swing auxiliary pilot pressure. cylinder bottom side to sup-
Function plement pump oil flow.

• If spool is bound in the fully • If spool is bound in the fully • Arm regenerative function is
opened position, what ever is opened position, swing park- inoperable.
operated, at this time flow ing brake is kept released.
combiner valve is shifted. (Machine vibrates while trav-
• If spool is bound in the fully eling.)
closed position, when travel • If spool is bound in the fully
and front/swing combined op- closed position, swing parking
Symptoms in control eration is made, machine mis- brake is kept applied. (Drag-
system when trouble tracks to the left. (left travel ging is felt.)
occurs. speed is slow.) • If spool is bound in the fully
closed position, the pressure
sensor (Front) is always
turned OFF. Thus the engine
speed isn’t faster when the
control lever is operated dur-
ing the auto-idle control.

• Same as described above. • Same as described above. • Arm speed is extremely slow
if it is kept close.
• Arm roll-out isn’t operated
smoothly if it is kept open.
Symptoms in machine
operation when trou-
ble occurs.

By Fault Code   

Eval-
By Monitor   
uation
Function
Using Test   
Harness
Others   

NOTE   

Descriptions of Con- T3-6 T3-3 T3-3

trol (Operational Prin-
ciple Section in T/M)

T5-4-14
 TROUBLESHOOTING / Troubleshooting B
(Blank)

T5-4-15
 TROUBLESHOOTING / Troubleshooting B
CORRELATION BETWEEN TROUBLE
SYMPTOMS AND PART FAILURES
This table indicates the relationship between machine
troubles and parts contributing to the cause of the
trouble if failed.
Engine System Troubleshooting
E-1 E-2 E-3 E-4
Starter doesn’t rotate. Although starter ro- When engine control dial is Even if engine control
Trouble tates, engine doesn’t fully rotated, engine stalls. dial is rotated, engine
Symptom start. Occasionally engine stalls speed remains un-
during operation with engine changed.
control dial fully rotated and
auto-idle ON. Engine speed
is slower than specification
in all operating range. Idle
speed is faster or slower
Parts than specification.
MC (Main Controller) z z z
QOS Controller
EC Motor z z
EC Sensor { z
Pump 1 Delivery Pressure
Sensor
Pump 2 Delivery Pressure
Sensor
Pump 1 Displacement Angle
Sensor
Pump 2 Displacement Angle
Sensor
Pressure Sensor (Travel)
Pressure Sensor (Swing⋅Front
Attachment)
Pressure Sensor (Swing)
Pressure Sensor (Boom Raise)
Pressure Sensor (Arm Roll-In)
Pressure Sensor (Auxiliary)
N Sensor
Hyd. Oil Temperature Sensor
Coolant Temperature Switch
Key Switch z
Engine Control Dial z
Auto-Idle/Acceleration Selector
Power Mode Switch {
Engine Learning Switch z
Battery Relay z
Glow Plug Relay
Engine Electrical Equipment z
Engine Unit z z z
Governor z z z
Check batteries. Check fuel system Check fuel cut-off handle Check engine control
(Filters and piping). and engine control cable. cable.
Remarks Be sure to perform engine
learning after replacing en-
gine.

T5-4-16
 TROUBLESHOOTING / Troubleshooting B

NOTE: The trouble symptoms in this table are de- In case more than one trouble occurs at
scribed provided that each trouble occurs the same time, find out all faulty compo-
independently. nents while checking all suspected com-
ponents in each trouble symptom.

E-5 E-6 E-7 E-8 E-9

Engine speed doesn’t In the HP mode, engine In the HP mode, engine Even if key switch is Malfunction of auto idle.
increase after engine is speed is not increased speed is increased dur- turned OFF, engine
started. during arm roll-in or ing operations other than doe-sn’t stop.
boom raise. arm roll-in or boom
raise.

z z z { z

{ {
{

{ { z

{ {
{ {

z {

z
z
{

{ {
{ {

z : Related, required to check { : Related. However, in case this component fails,

other trouble symptom will be more noticeable so
that this component will not be the direct cause of
the trouble concerned.

T5-4-17
 TROUBLESHOOTING / Troubleshooting B

NOTE: The trouble symptoms in this table are de- In case more than one trouble occurs at
scribed provided that each trouble occurs the same time, find out all faulty compo-
independently. nents while checking all suspected com-
ponents in each trouble symptom.

E-10 E-11 E-12 E-13

Malfunction of E-mode. Malfunction of Engine stalls within Engine stalls during
Trouble auto-acceleration. several seconds after operation under ad-
Symptom engine has started. verse condition such as
at high altitude.

Parts

MC (Main Controller) z z z
QOS Controller
EC Motor
EC Sensor
Pump Control Solenoid Valve z

Pump 1 Delivery Pressure

{
Sensor
Pump 2 Delivery Pressure
{
Sensor
Pump 1 Displacement Angle {
{
Sensor
Pump 2 Displacement Angle {
{
Sensor
Pressure Sensor (Travel) {
Pressure Sensor (Swing⋅Front
Attachment)
Pressure Sensor (Swing) {
Pressure Sensor (Boom
{
Raise)
Pressure Sensor (Arm Roll-In) {
Pressure Sensor (Auxiliary)
N Sensor z
Hyd. Oil Temperature Sensor
Coolant Temperature Switch
Key Switch
Engine Control Dial
Auto-Idle/Acceleration Selec-
z
tor
Power Mode Switch z
Work Mode Switch
Quick Idle Switch
Engine Learning Switch z
QOS Controller
Glow Plug Relay
Engine Electrical Equipment
Engine Unit {
Governor z
Pump Regulator {
Check fuel system for
clogging.
Remarks

z : Related, required to check that this component will not be the direct cause of
{ : Related. However, in case this component fails, the trouble concerned.
other trouble symptom will be more noticeable so

T5-4-18
 TROUBLESHOOTING / Troubleshooting B

E-14
Engine is difficult to
start at low tempera-
ture.

z
z
z
{

Check batteries.

T5-4-19
 TROUBLESHOOTING / Troubleshooting B

All Actuator System Troubleshooting

A-1 A-2 A-3 A-4
All actuator speeds Left travel is inoperable Right travel is in oper- Actuator doesn’t stop
Trouble are slow. during single travel op- able during single even if control lever is
Symptom eration. Single swing travel operation. Single returned to neutral.
operation speed is slow. bucket operation
Arm is slightly slow dur- speed is slow. Boom is
ing arm level crowding. not raised properly
during arm level
crowding.
Parts
MC (Main Controller) z
Pump 1 Control Solenoid Valve
Pump 2 Control Solenoid Valve
N Sensor
Spool z
Main Relief Valve z
Main Pump z z z
Work Mode Switch z z z
Pilot Pump z
Pilot Valve z
Pilot Relief Valve z
Pump Control Pressure Sensor
z
(4-Spool)
Pump Control Pressure Sensor
z
(5-Spool)

Pump 1 Flow Rate Control Valve z

Pump 2 Flow Rate Control Valve z

Pump 1 Displacement Sensor z

Pump 2 Displacement Sensor z
Pump 1 Delivery Pressure Sen-
z
sor
Pump 2 Delivery Pressure Sen-
z
sor
Precision Mode Switch z
Pressure Sensor (Swing) z
Overheat Switch z
Refer to F1.
Remarks

T5-4-20
 TROUBLESHOOTING / Troubleshooting B

NOTE: The trouble symptoms in this table are de-

scribed provided that each trouble occurs
independently.
In case more than one trouble occurs at
the same time, find out all faulty compo-
nents while checking all suspected com-
ponents in each trouble symptom.

z : Related, required to check

{ : Related. However, in case this component fails,
other trouble symptom will be more noticeable so
that this component will not be the direct cause of
the trouble concerned.

T5-4-21
 TROUBLESHOOTING / Troubleshooting B

Front Attachment System Troubleshooting

F-1 F-2 F-3 F-4
All front attachment ac- Malfunction of power Some cylinder are in- Arm doesn’t work
Trouble tuator power is weak. digging and precision operable or speeds are smoothly in arm roll-in
Symptom mode. slow. digging single opera-
tion.

Parts

MC (Main Controller) z
Solenoid Valve Unit (SA) z
Solenoid Valve Unit (SC)
Solenoid Valve (Swing Pref-
erence Circuit)
Pressure Sensor (Swing)
Power Digging Switch, Preci-
z
sion Mode Switch
Work Mode Switch
Spool z z
Main Relief Valve z z
Overload Relief Valve z z
Holding Valve
Load Check Valve
Boom Mode Selector Switch
Boom Overload Relief Selec-
tor Valve
Arm Regenerative Valve z
Shockless Valve (Outside of
z
Signal Control Valve)
Shockless Valve (Inside of
z
Signal Control Valve)
Shuttle Valve (Signal Control
z
Valve)
Pilot Valve z
Cylinder
Refer to A-2 and A-3
Remarks

T5-4-22
 TROUBLESHOOTING / Troubleshooting B

NOTE: The trouble symptoms in this table are de- In case more than one trouble occurs at
scribed provided that each trouble occurs the same time, find out all faulty compo-
independently. nents while checking all suspected com-
ponents in each trouble symptom.

F-5 F-6 F-7 F-8 F-9

When doing combined Jack up is mode even if When operating the lever Front attachment drifts During combined opera-
operation of siring and the boom mode selector (boom raise or arm remarkably. tion of front attachment
boom raise, boom raise switch is ON. roll-out), it doesn’t start to and swing, front attach-
speed is slow. move right away. ment speed is slow.

{ { z

z {

z z
z z

z
z
z
z

z z
Refer to F-5.

z : Related, required to check

{ : Related. However, in case this component fails,
other trouble symptom will be more noticeable so
that this component will not be the direct cause of
the trouble concerned.

T5-4-23
 TROUBLESHOOTING / Troubleshooting B

Swing/Travel/Other System Troubleshooting

S-1 S-2 S-3 T-1
Swing is slow or un- Swing is too fast. In the trenching mode, Both right and left
Trouble moving. swing is slow in com- tracks do not rotate or
Symptom bined operation of rotate slowly.
swing and boom raise.

Parts

MC (Main Controller) z {
Solenoid Valve (Swing Pref-
erence Circuit)) z z z
Solenoid Valve Unit (SA)
Solenoid Valve Unit (SB) {
Pressure Sensor (Travel) {
Pressure Sensor (Swing) z
Travel Mode Switch
Pump Device
Spool
Check Valve
Flow Combiner Valve
Swing Parking Brake Release
z
Spool (Signal Control Valve)
Pump Control Pressure Sen-
sor (4-Spool)
Pump Control Pressure Sen-
sor (5-Spool)
Pump 1 Flow Control Valve
(Signal Control Valve)
Pump 2 Flow Control Valve
(Signal Control Valve)
Flow Combiner Control Spool
(Signal Control Valve)
Shuttle Valve (Signal Control
z
Valve)
Swing Device z
Travel Device
Center Joint
Pilot Valve z {
Pump 1 Displacement Angle
Sensor
Pump 2 Displacement Angle
Sensor
Main Relief Valve z
Work Mode Switch z {
Refer to A-2. Refer to T-4.
Remarks

T5-4-24
 TROUBLESHOOTING / Troubleshooting B

NOTE: The trouble symptoms in this table are de- In case more than one trouble occurs at
scribed provided that each trouble occurs the same time, find out all faulty compo-
independently. nents while checking all suspected com-
ponents in each trouble symptom.
T-2 T-3 T-4
One side track doesn’t Machine mistracks Fast travel is inoperable.
rotate or rotates during travel and front Travel mode doesn’t
slowly. Machine mis- attachment combined change from slow mode
tracks. operation. to fast mode.

z
{
z
z
z

z z
z
z

In case either bucket

or swing is also slow,
refer to A-2 or A-3.

z : Related, required to check

{ : Related. However, in case this component fails,
other trouble symptom will be more noticeable so
that this component will not be the direct cause of
the trouble concerned.

T5-4-25
 TROUBLESHOOTING / Troubleshooting B

O-1 O-2 O-3 O-4

Wiper is inoperable or Malfunction of coun- Malfunction of auto lu- Malfunction of air condi-
Trouble not retracted terweight removal de- brication system. tioner.
Symptom vice.

Parts

MC (Main Controller) {
Solenoid Valve Unit (SA) {
Pressure Sensor
z
(Counterweight Removal)
Main Relief valve {
Counterweight Removal Cyl-
z
inder
Counterweight Removal Pilot
z
Valve
Refer to T5-4-68. Refer to T5-4-72. Refer to T5-4-75.

Remarks

NOTE: The trouble symptoms in this table are de- z : Related, required to check
scribed provided that each trouble occurs { : Related. However, in case this component fails,
independently. other trouble symptom will be more noticeable so
In case more than one trouble occurs at that this component will not be the direct cause of
the same time, find out all faulty compo- the trouble concerned.
nents while checking all suspected com-
ponents in each trouble symptom.

T5-4-26
 TROUBLESHOOTING / Troubleshooting B
ENGINE SYSTEM TROUBLESHOOTING
E-1 Starter doesn’t rotate.

Related Fault Code: None

• This trouble has nothing to do with the electronic

control system such as the MC.
• Check for loose harness connections beforehand.

Faulty starter or
YES faulty harness
between starter
Check if voltage at and battery relay.
YES battery relay
terminal A is 24 V.
Faulty battery
NO relay.
Check if both voltages
YES at key switch terminal
#5 and #6 are 24 V.
· Key switch: START YES Faulty key switch.
Check for
Check if battery
continuity between
voltage and
battery positive
electrolyte density NO terminal and key
is normal, and Faulty harness
switch terminal #1.
fusible link (45 A) is between battery
not blown. NO and key switch.
· Voltage: More than
24 V
Density: 1.25 to
1.28 Faulty battery or
NO fusible link.

Key Switch Battery Relay

T16J-05-04-001
T105-07-04-002
Terminal A

T5-4-27
 TROUBLESHOOTING / Troubleshooting B
E-2 Although starter rotates, engine doesn’t
start.

Related Fault Code: None

• Check the fuel cut lever position during cranking.

If the position is normal, the engine unit and/or
fuel system may have trouble.
• Check for loose harness connections beforehand.

YES Faulty engine.

· Refer to Engine Shop Manual.

Check if governor lever moves

to the START position when
key switch is turned ON. YES Faulty EC motor.
· Key switch: ON

Check if EC motor drive

NO circuit is normal.
· Test harness: 4274589
(ST 7125) Faulty MC.
NO
· Refer to T4-6-2.

• Governor Lever and Fuel Cut Lever

1 2 3 4

T16J-04-02-008
1 - Fuel Cut Lever
2 - Fuel Cut-Off Cable
(Fuel Cut-Off Handle)
3 - Governor Lever
4 - Governor Cable
(From EC Motor)

T5-4-28
 TROUBLESHOOTING / Troubleshooting B
• Governor Lever Position

A - Key Switch OFF (Engine Stop Position)

B - Key Switch ON (Engine Start Position)

B A
FULL STOP

STOP FULL

T16J-04-02-008

• Fuel Cut Lever Position

A - Fuel Cut-Off Handle Pulled Position

B - Fuel Cut-Off Handle Returned Position
A B

T16J-04-02-008

T5-4-29
 TROUBLESHOOTING / Troubleshooting B
E-3 When engine control dial is fully rotated,
engine stalls.
Occasionally engine stalls during operation
with engine control dial fully rotated and
auto-idle ON.
Engine speed is slower than specification in
all operating ranges.
Idle speed is faster or slower than
specification.

Related Fault Code: 06

• In case engine learning has not been performed

or engine learning has been incorrectly performed,
engine speed becomes slower than specification
across the operating range.
• In case the EC sensor is faulty, engine speed is
controlled based on the governor lever position,
which is judged as the idle position when the key
switch is turned ON. Accordingly, discrepancies in
engine speed from specification will result.
Depending on where the governor lever is
positioned when the key switch is turned ON,
discrepancy will differ, causing this trouble to be
not reproducible.
• Check if the power mode switch position is HP or
P mode.
• Refer to pages for Engine Learning in the
SYSTEM/Control System group in the T/M
(Operational Principle).
• Check for loose harness connections beforehand.

Return fuel cut

YES lever to original
position.

Check if fuel cut YES Faulty EC sensor.

lever has been
moved up to half
way stroke. · Refer to T4-6-2.

Check if fault code

NO 06 is displayed. YES End.
Check if problem is
corrected after
NO engine learning.
· Refer to T4-6-2. Monitor engine
NO learning status.
· Monitor item:
Engine learning
control

T5-4-30
 TROUBLESHOOTING / Troubleshooting B

YES Faulty engine and/or fuel

system.
OK Check if governor lever comes
in contact with stopper when
performing engine learning. Faulty control cable and/or
incorrectly adjusted engine
NO governor lever.
ト リ 良
· Adjust engine speed.
(Refer to T4-6-2.)

Faulty MC, faulty learning

switch, or broken harness
NOT OK between learning switch and
MC.
· Refer to T4-6-2.

T5-4-31
 TROUBLESHOOTING / Troubleshooting B
E-4 Even if engine control dial is rotated, engine
speed remains unchanged.

Related Fault Code: 07

• If the EC fails, the engine will not stop with the

key switch ON.
• Check if the quick idle switch is turned off.
• Check for loose harness connections beforehand.

Faulty engine control dial or

YES broken harness between
engine control dial and MC.
Check if fault code 07 is
displayed. Using Dr. EX,
monitor engine control dial
angles (standard voltages). YES Faulty EC motor.
Check if voltages are normal.
Install test harness (ST 7125)
· Standard voltages to EC motor. Check if lamp · Refer to T4-6-2.
minimum speed position: comes ON while turning
0.3 to 1 V NO engine control dial.
Maximum speed position: Faulty MC or broken harness
4.0 to 4.7 V between MC and EC motor.
· Possible to display with built-in NO
diagnosing system · Refer to T4-6-2.

E-5 Engine speed doesn’t increase after engine

is started.

Related Fault Code: 19

• Refer to the pages for the Auto Warming Up

Control in the SYSTEM / Control System group in
the T/M (Operational Principle).
• Check for loose harness connections beforehand.

More than 0 °C
when starting Normal.

NO Monitor oil Faulty key switch

temperature. YES or broken harness
Monitor key switch. between key
· Monitor item: switch and MC.
Hydraulic oil Check if displayed
“ky” is highlighted
temperature Lower than 0 °C
· Possible to display when starting in response to key Faulty MC.
Check if fault code with built-in switch operation. NO
19 is displayed. diagnosing system · Monitor item: Key · Refer to T4-6-2.
switch

Faulty hyd. oil

temperature sensor
or broken harness
YES
between hyd.
oil temperature
sensor and MC.

T5-4-32
 TROUBLESHOOTING / Troubleshooting B
E-6 In the HP mode, engine speed is not
increased during arm roll-in or boom raise.

Related Fault Code: 10, 11, 15 and 16

• Sensors detect the conditions necessary to

operate the HP mode. Therefore, if any of these • Refer to the pages for HP Mode Control in the
sensor fails, the HP mode becomes inoperable. SYSTEM / Control System group in the T/M
• Pressure sensors (arm roll-in and boom raise) (Operational Principle).
and pump 1 and 2 delivery pressure sensors are • Check for loose harness connections beforehand.
also engaged in the HP mode control. However, if
these sensors fail, other operating functions will
be also affected. (Refer to the relationship
between machine trouble symptoms and related Faulty power mode
parts on page T5-4-2.) switch or broken
NO harness between
power mode switch
Monitor power mode and MC.
switch. Check if
indication HP is
NO highlighted when
YES Faulty engine.
power mode switch
is turned to “HP Check if governor
mode”. lever comes in
· Monitor item: E/P/HP YES contact with full-side
mode switch stopper while
Check if any fault Faulty MC.
relieving boom raise
codes are NO
circuit pressure. · Refer to T4-6-2.
displayed.

Faulty
corresponding
sensor or broken
YES
harness between
sensor and MC.
· Fault Codes:
E-7 In the HP mode, engine speed is increased Pump 1 delivery pressure sensor: 10
during operations other than arm roll-in, Pump 2 delivery pressure sensor: 11
boom raise and travel. Pilot pressure sensor (boom raise): 15
Pilot pressure sensor (arm roll-in): 16
Related Fault Code: 04, 10, 11, 15 and 16
YES End.

NO Check if problem is Check if governor NO Faulty engine.

corrected after the lever comes in contact
engine learning. with full-side stopper
Check if any fault when engine control
codes are NO
dial is turned in full
displayed. Faulty corresponding
sensor or shirt circuited · Engine: Running Faulty MC.
YES harness between sensor · Operation other than YES
and MC. arm roll-in and boom
raise. · Refer to T4-6-2.
· Fault Codes:
Short circuited in sensor circuit: 04
Pump 1 delivery pressure sensor: 10
Pump 2 delivery pressure sensor: 11
Pilot pressure sensor (boom raise): 15
Pilot pressure sensor (arm roll-in): 16

T5-4-33
 TROUBLESHOOTING / Troubleshooting B
E-8 Even if key switch is turned OFF, engine
doesn’t stop. (In case the engine doesn’t
stop, stop the engine by pulling the engine
stop handle located under the seat stand.
Then, begin inspection.)

Related Fault Codes: 06 and 07

• Probably symptoms such as “Engine speed is

slower than specification in all operating ranges”
or “Even if engine control dial is rotated, engine
speed remains unchanged” will come up. Perform
troubleshooting for these symptoms.

T5-4-34
 TROUBLESHOOTING / Troubleshooting B
E-9 Malfunction of auto-idle

• Although all control levers are in neutral position,

auto-idle does not function.

Related Fault Code: 18

• In case trouble symptoms E1 to E8 are

recognized, perform the troubleshooting of these
troubles beforehand.
• Although the failure in pressure sensors (travel
and swing ⋅ front attachment) will have relevance
to malfunction of the auto-idle control. However, if
these sensors fail, other operating functions will
also be affected. (Refer to the relationship
between machine trouble symptoms and related
parts on page T5-4-2.)
• Refer to the pages for Auto-Idle Control in the
SYSTEM / Control System group in the T/M
(Operational Principle).
• Check for loose harness connections beforehand. Normal (Turn power
mode switch to a
YES position other than
the E mode.)

Check if power Monitor pressure Bound swing

YES
mode switch is in sensor (swing ⋅front YES parking brake spool
the E mode attachment). in signal control
position. Check if display is valve.
“Sw/Fr”.
Monitor auto-idle Monitor pressure
YES Faulty pressure
switch. Check if NO sensor (travel). Exchange
sensor.
displayed “AI” is Check if pressure abnormal sensor
turned OFF or ON varies between 0 to with other sensor.
in response to 3.9 MPa (0 to 40 NO Check if auto-idle Faulty MC.
2
auto-idle switch kgf/cm ). system operates NO
operation. properly.
· Monitor item: · Refer to T4-6-2.
· Monitor item: Swing/front attachment ope.
Auto-idle / auto-accel · Travel control pressure.
switch · Front operation/stop Faulty auto-idle /
Travel operation/stop auto acceleration
selector or broken
NO
harness between
• Although the auto-idle/auto-acceleration selector is auto-idle /
auto-acceleration
turned OFF, the auto-idle functions. selector and MC.

• Be sure to separate the auto-idle control from the

auto-acceleration control.

YES Shorten harness between

MC and auto-idle/
auto-acceleration selector.
Monitor the
auto-idle/auto-acceler
ation selector. Check if
the display is “AI”.
Faulty MC.
· Monitor item: Auto-idle /
auto-accel switch NO
· Auto-idle / · Refer to T4-6-2.
auto-acceleration
selector: OFF

T5-4-35
 TROUBLESHOOTING / Troubleshooting B
E-10 Malfunction of E mode

• Even if power mode switch is turned to the E mode

position, engine speed remains unchanged. (Engine
speed doesn’t decrease.)

Related Fault Code: None

• In case trouble symptoms E-1 to E-9 are

recognized, perform the troubleshooting of these
troubles beforehand.
• Refer to the pages for E Mode Control in the
SYSTEM / Control System group in the T/M
(Operational Principle).
• Check for loose harness connections beforehand. Faulty power mode switch or
NO
broken harness between
Monitor power mode switch. power mode switch and MC.
Check if displayed “E Mode” is
turned OFF or ON in response
to power mode switch
operation. Faulty MC.
· Monitor item: YES
E/P/HP mode switch · Refer to T4-6-2.

• Though the power mode switch isn’t turned to E

mode, the engine speed decreases.

YES Shorten harness between MC

and power mode switch.

Monitor the power mode

switch. Check if the display is
“E”.
Faulty MC.
· Monitor item: E/P/HP mode switch. NO
· Power mode switch: P mode · Refer to T4-6-2.

T5-4-36
 TROUBLESHOOTING / Troubleshooting B
E-11 Malfunction of auto-acceleration

• Auto-acceleration system is inoperable.

Related Fault Code: 8, 9, 10, 11, 12, 13, 14, 15, 16,
and 18

• In case trouble symptoms E-1 to E-11 are

recognized, perform the troubleshooting of these
troubles beforehand.
• Although the failure in pressure sensors (travel,
swing, boom raise, and arm roll-in), pump 1 and 2
delivery pressure sensors, and pump 1 and 2
displacement angle sensors will have relevance
to malfunction of the auto-acceleration control.
However, if these sensors fail, other operating
functions will also be affected. (Refer to the
relationship between machine trouble symptoms
and related parts on page T5-4-2.)
• Refer to the pages for Auto-Acceleration Control
in the SYSTEM / Control System group in the T/M
(Operational Principle).
• Check for loose harness connection beforehand.
Faulty auto-idle /
NO auto-acceleration selector or
broken harness between
Monitor auto-acceleration switch. auto-idle / auto-acceleration
Check if displayed “AA” is turned selector and MC.
OFF or ON in response to
auto-idle / auto-acceleration
selector operation. Faulty MC.
· Monitor item: YES
auto-idle / auto-acceleration · Refer to T4-6-2.
switch

• Though the auto-idle/acceleration switch is turned

OFF, the auto-acceleration functions.

• Be sure to separate the auto-idle control from the

auto-acceleration control.
Shorten harness between MC
YES
and auto-idle /
auto-acceleration selector.
Monitor the auto-idle/
acceleration selector.
Check if the display is “AA”

· Monitor item: auto-idle / Faulty MC.

auto-acceleration switch NO
· Auto-idle / acceleration selector: · Refer to T4-6-2.
Auto-idle

T5-4-37
 TROUBLESHOOTING / Troubleshooting B
E-12 Engine stalls within several seconds after
engine has started.

Related Fault Code: None

• Refer to the pages for Engine Learning Control in

the SYSTEM / Control System group in the T/M
(Operational Principle).
• If the engine learning switch is turned to the
learning position, the engine will stall in 5 seconds
after the engine starts.
• Check for loose harness connections beforehand.

YES Normal (Return switch

to neutral.).

Check if engine
learning switch is
turned to the learning Faulty learning switch,
position. or short-circuited
harness between
learning switch and MC,
NO
or check fuel system for
clogging.

T5-4-38
 TROUBLESHOOTING / Troubleshooting B
E-13 Engine stalls during operation under
adverse condition such as at high altitude.

Related Fault Code: 05

• If speed sensing control is inoperable, the engine

will stall under adverse operating conditions.
• There are two sets of pump control solenoid
valves, pump displacement angle sensors and
regulators. It does not seen that both two sets fail
at the same time. If one of the two sets fails,
mistrack will be caused during travel.
• Check for loose harness connections beforehand.
Faulty MC, pump
NO control solenoid valve,
or misalignment of
pump displacement
angle sensor or
Measure pump flow misadjustment of pump
NO regulator.
rate. Check if pump
P-Q curve is normal. · Refer to Adjustment
group in Performance
· Refer to the Operational Test section.
Performance Test
Check if fault code 05 is section. Faulty engine.
displayed. YES
Monitor actual engine
speed. Check if engine
speed is abnormal.
· Monitor item:
Engine actual speed
Faulty N sensor, or
faulty harness
YES between N sensor
and MC.

T5-4-39
 TROUBLESHOOTING / Troubleshooting B
E-14 Engine is difficult to start at low
temperature. (During cold weather or in
cold districts, the engine is difficult to start
or doesn’t start although pre-heated.)

Related Fault Code: None

• Check if electricity is routed to the glow plugs.

Check the glow plugs for any abnormality.
• The pre-heat system operates only when coolant
temperature is below 10 °C (50 °F). When
coolant temperature is higher than 10 °C (50 °F),
the pre-heat system doesn’t operate.
• Check battery at the same time.
• Check for loose harness connections beforehand.

YES Faulty coolant temperature

switch.

Disconnect coolant
temperature switch. Check if
voltage at glow plug is 20 to 24
YES Faulty QOS controller.
V.
· Key switch: ON
Disconnect QOS controller.
Ground harness end connector
NO terminal #4 to vehicle frame.
Check if problem is corrected.

· Using a clip, ground from the Measure each glow plug

reverse side of the connector NO resistance.
without disconnecting.
· Key switch: ON
· Before measuring, remove
copper plates connecting
each glow plug.

• Measurement of Glow Plug Voltage and Resistance

Voltage Check Resistance Check

Remove
the
copper
plate.

Specification: 20 to 24 V Specification: Below 10 Ω

T105-07-04-006 T105-07-04-007

T5-4-40
 TROUBLESHOOTING / Troubleshooting B

∞Ω Faulty glow plug.

YES Faulty glow relay.

Disconnect glow relay.

YES Connect harness end
connector terminal #4 to
vehicle frame. Check if
voltage at glow plug is 20
to 24 V. Faulty engine unit.
Disconnect glow relay. · Key switch: ON NO
Check if voltage at glow
relay harness end · Refer to the Engine Shop Manual.
Below 10 Ω connector terminals #1 or
#3 is 20 to 24 V.
In case voltage at terminal #1
· Key switch: ON is 0 V, harness between glow
relay and batteries is broken.
In case voltage at terminal #3
NO is 0 V, harness between glow
relay and key switch terminal
M is broken.

· Verify that fuse #20 is normal.

T5-4-41
 TROUBLESHOOTING / Troubleshooting B
ALL ACTUATOR SYSTEM TROUBLE-
SHOOTING
A-1 All actuator speeds are slow.

Related Fault Code: None

• Reduction in pump 1 and 2 flow rate due to some

reasons or faulty pilot system may cause this trou-
ble.
• Although speed is satisfactory, in case power is
weak, refer to the troubleshooting for faulty relief
valve (F-1).
• Check for loose harness connections beforehand.

NO Work mode switch

failure.

Check if work
mode can be NO Turn precision mode
shifted. switch to OFF, or
Check if precision faulty precision mode
· Monitor item: Work mode is OFF. switch.
mode switch YES
· Monitor item: Precision A
YES
mode switch
YES Faulty pilot pump or
clogged pilot filter.

Check if same
NO symptom still ap-
pears after disas-
sembling, cleaning,
and adjusting pilot End.
relief valve. NO

Check if primary
A pilot pressure is Faulty N sensor or
normal. YES broken harness in N
sensor circuit.
· Fully boom raised or arm
roll-in
· Monitor item: Boom raise
pilot pressure, arm dig- Monitor actual en-
ging pilot pressure gine speed. Check
if abnormal speed NO Main relief valve fail-
YES
is indicated. ure.

· Monitor item: Engine

actual speed Check if main relief
· Possible to display in pressure is normal.
built-in diagnosing NO
system · Refer to Opera-
Check if letters
tional Performance
“OVERHEAT” for
Test section for
pressure meas- YES overheat switch turn
reverse video.
urement procedure
· Key switch: ON
· Monitor item: Eng.
overheat switch

T5-4-42
 TROUBLESHOOTING / Troubleshooting B

YES
Overheat of coolant.

Check if coolant tem-

perature exceeds 98 °C
(208 °F).

Check overheat switch

NO circuit.

T5-4-43
 TROUBLESHOOTING / Troubleshooting B
A-2 Left travel is inoperable during single travel
operation. Single swing operation speed is
slow. Arm is slightly slow during arm level
crowding. (All problems occur at the same
time.)

Related Fault Code: 09, 11, 13, 14, 21

• The pump 2 flow rate is minimized due to some

reasons. Accordingly, the left travel and swing mo-
tors, which are driven by pressure oil from pump 2,
moves very slow.
• Pressure oil from pump 1 is also routed to the arm
and boom cylinders so that the arm and boom can
move at a slightly slow speed in single operation.
However, in level crowd operation, pressure oil is
routed to the boom prior to the arm so that arm
speed becomes very slow.
• If swing operation speed is normal, monitor swing
pilot pressure and, check if the pressure is 0 MPa
while swing control lever is in neutral.
• Check for loose harness connections beforehand.
• Refer to the SYSTEM / Hydraulic System group in
the T/M (Operational Principle).
Misalignment of pump
NO 2 displacement angle
sensor or pump 2 fail-
ure.
Check if pump 2 de-
sired displacement is · Refer to Adjustment
minimum value with group in Perform-
control levers in neu- ance Test section.
tral.
Also, check if pump 2 YES Faulty pump 2.
desired displacement Monitor pump 2
is maximum when left pump control pres-
travel lever is operated NO sure. Check if
full stroke white left pressure increases
track is jacked up. in proportion to left
Check if any fault travel lever stroke. Bound pump 2 flow
· Monitor item: Pump 2 codes are dis- rate control valve in
YES played. NO signal control valve.
desired displacement. · Monitor item: Pump 2
flow control pressure
· Possible to display with
built-in diagnosing sys-
tem.

Faulty corresponding
sensor or broken har-
YES ness between sensor
and MC.
· Fault code: Pump 2 dis-
placement angle sensor: 09
Pump 2 delivery pressure
sensor: 11
Pump control pressure sen-
sor (5-spool): 13
Pump 2 control solenoid
valve: 21

T5-4-44
 TROUBLESHOOTING / Troubleshooting B
A-3 Right travel is inoperable during single
travel operation. Single bucket operation
speed is slow. Boom is not raised properly
during arm level crowding. (All problems
occur at the same time.)

Related Fault Code: 08, 10, 12, 20

• The pump 1 flow rate is minimized due to some

reasons. Accordingly, the right travel motor and
bucket cylinder, which are actuated by pressure oil
from pump 1, moves very slow.
• Pressure oil from pump 2 is also routed to the arm
and boom cylinders so that the arm and boom can
move at a slightly slow speed in single operation.
However, in level crowd operation, pressure oil is
routed to the arm prior to the boom so that boom is
scarcely raised.
• Check for loose harness connections beforehand.
• Refer to the SYSTEM / Hydraulic System group in
the T/M (Operational Principle).

Misalignment of pump
NO 1 displacement angle
sensor or pump 1 fail-
ure.
Check if pump 1 de-
sired displacement is · Refer to Adjustment
minimum value with group in perform-
control levers in neu- ance Test section.
tral.
Also, check if pump 1 YES Faulty pump 1.
desired displacement Monitor pump 1
is maximum when left pump control pres-
travel lever is operated NO sure. Check if
full stroke white left pressure increases
track is jacked up. in proportion to left
Check if any fault travel lever stroke. Bound pump 1 flow
· Monitor item: Pump 1 codes are dis- rate control valve in
YES played. NO signal control valve.
desired displacement. · Monitor item: Pump 1
flow control pressure
· Possible to display with
built-in diagnosing sys-
tem.

Faulty corresponding
sensor or broken har-
YES ness between sensor
and MC.
· Fault code: Pump 1 dis-
placement angle sensor: 08
Pump 1 delivery pressure
sensor: 10
Pump control pressure sen-
sor (4-spool): 12
Pump 1 control solenoid
valve: 20

T5-4-45
 TROUBLESHOOTING / Troubleshooting B
A-4 Actuator doesn’t stop even if control lever is
returned to neutral.

Related Fault Code: None

• Bound spool in the pilot valve or bound main spool

in the control valve is suspected.

YES Faulty pilot valve.

· When control lever is in neu-

Check if actuator stops when tral, pilot pressure is routed to
pilot control shut-off lever is spool end in control valve.
raised.

Faulty control valve.

NO
· Although pilot pressure is not
routed to spool end in control
valve, spool is kept opened
due to binding of spool.

T5-4-46
 TROUBLESHOOTING / Troubleshooting B
(Blank)

T5-4-47
 TROUBLESHOOTING / Troubleshooting B
FRONT ATTACHMENT SYSTEM TROU-
BLESHOOTING
F-1 All front attachment actuator power is weak.

Related Fault Code: None

• In case operating speeds are extremely slow,

pump control may be malfunctioning (A-2 and/or
A-3). Faulty pilot system may also cause this trou-
ble.

30.4 to 32.5 MPa Main relief valve should be

2
(310 to 335 kgf/cm ) normal. Find out cause of
trouble by tracing other trou-
ble symptoms.
Monitor pump 1 and 2 delivery
pressures.
· Monitor item: Pump 1 and 2 de- Adjust main relief valve.
livery pressure Less than 30.4 MPa
2
· Possible to display with built-in (310 kgf/cm )
diagnosing system
· Relieve boom, arm, and bucket
circuits.
· Power mode switch: HP
· Work mode: Digging

F-2 Malfunction of power digging and precision

mode.

Related fault Code: None

• Refer to the pages for the Power Digging Control

and Precision Mode Control in the SYSTEM /
Control System group in the T/M (Operational
Principle).
• If the flow rate is reduced, pump control system
might be failed. Refer to A-2 and A-3.
• Check for loose harness connections beforehand.
Pressure Increases. Faulty power digging /
2
Less than 30.4 MPa (310 kgf/cm ) precision switch or bro-
↓ NO
2 Normal. ken harness between
31.9 MPa (325 kgf/cm ) power digging / preci-
sion switch and MC.
Monitor pump 1
and 2 delivery
pressures. Monitor power dig-
ging switch and
· Monitor item: YES
precision mode
Pump 1 and 2 deliv- Monitor solenoid valve
Pressure switch. Check if
ery pressure (SA) pressure.
doesn’t in- display is normal.
· Possible to display Check if pressure is
crease.
with built-in diagnos- · Monitor item: YES approx. 3.9 MPa (40
ing system Power digging switch 2
kgf/cm ).
· Check pump delivery Precision mode switch
pressure change · Monitor item:
while travelling. Power Boost Control
· Power mode switch: Valve Out NO
HP mode

T5-4-48
 TROUBLESHOOTING / Troubleshooting B

Connector (Harness End Connector Viewed from the open End Side)

Solenoid Valve Unit (SA)

T183-05-04-010

Exchange solenoid
Faulty main relief valve.
valve unit (SA) with NO
solenoid valve unit
YES (SB).
Disconnect solenoid Check if power digging
valve unit (SA). Check system and precision
if voltage at solenoid Faulty solenoid valve unit
mode system operate (SA).
valve unit (SA) harness properly. YES
end connector terminal
#1 is 24 V.
Faulty harness between so-
· Precision mode switch: lenoid valve unit (SA) and MC.
ON NO

Faulty MC.

· Refer to T4-6-2.

T5-4-49
 TROUBLESHOOTING / Troubleshooting B
F-3 Some cylinders are inoperable or speeds are
slow.

Related Fault Code: None

• When other actuators (travel and swing motors)

operate normally, the pilot pump (primary pilot
pressure) is considered to be normal.
• Refer to F-6 if boom lowering is slow.

YES Bound control valve

spool or faulty cylinder
(faulty seal kit).
Monitor pump control YES Check if overload
pressure. Check if relief pressure is
pump control pres- normal.
sure changes Faulty overload relief
YES smoothly while mov- NO valve.
ing control lever
slowly.
Monitor or meas- · Monitor item: Faulty shuttle valve in
ure secondary pilot Pump 1 flow control NO signal pressure con-
pressure. Check if pressure, pump 2 flow trol valve.
secondary pilot control pressure
pressure is normal. · Possible to display with
· Secondary pilot built-in diagnosing sys-
tem YES Bound shockless
pressure: valve spool.
Refer to Operational Check if secondary
Performance Test pilot pressure at inlet
Section. NO port to signal control
· Monitor item: Boom valve. Faulty pilot valve.
raise pilot pressure, NO
arm roll-in pilot pres- · Check only when
sure boom is not raised.
· Possible to display In case cylinders
with built-in diagnos- other than boom are
ing system abnormal, skip this
step and proceed to
the NO line.

T5-4-50
 TROUBLESHOOTING / Troubleshooting B
F-4 Arm doesn’t work smoothly in arm roll-in
digging single operation.

Related Fault Code: None

• Refer to the COMPONENT OPERATION / Con-

trol Valve group in the T/M (Operational Princi-
ple).
Faulty arm regenerative valve
YES
(Disassemble to clean, or re-
place.).
Check if arm regenera-
tive valve is bound or
scored.
Faulty control valve or bound
NO control valve spool.

F-5 When doing combined operation of swing

and boom raise, boom raise speed is slow.

Related Fault Code: None

• If other operations except the swing / boom raise

are normal, the swing / boom operation seems to
fail.
• Check for loose harness connections beforehand.
• Refer to the pages for the Swing Preference Con-
trol in the SYSTEM / control System group in the
T/M (Operational Principle).
NO Faulty MC.

Check if the swing / · Refer to T4-6-2.

YES boom raise switch
pressures change in
response to the swing /
boom raise. Broken harness between MC
Check if voltage at so- NO and solenoid valve (swing
Monitor work mode lenoid valve (swing pref- preference circuit).
· Monitor item: Swing / boom erence) harness end
switch.
control valve out connector terminal #1 is
Check if display is nor- YES
mal. 24 V. Faulty solenoid valve (swing
YES preference).
· Monitor item: Work
mode switch
· Work mode switch: Dig- Faulty work mode switch or
ging mode broken harness between MC
NO and monitor.

Connector (Harness End Connector Viewed from the open End Side)
Solenoid Valve (Swing Preference)

T183-05-04-010

T5-4-51
 TROUBLESHOOTING / Troubleshooting B
F-6 Jack up is made even if the boom mode se-
lector switch is ON.

Related Fault Code: None

• Refer to the pages for Boom Mode Selector Con-

trol in the SYSTEM / Control System group in the
T/M (Operational Principle).
• Check for loose harness connections beforehand.
Exchange boom NO Faulty MC.
mode selection · Refer to T4-6-2.
switch with precision
Disconnect boom YES mode switch and
mode selector switch check if system oper-
and MC connector C. ates properly. Faulty boom mode
Check for continuity selector switch.
between boom mode · Boom mode selector YES
NO selector switch har- switch: ON
ness end connector Broken harness be-
terminal #1 and con- tween MC connector
nector C harness end C and boom mode
Monitor boom mode NO selector switch.
connector terminal
selector switch. Check
#10.
if displayed “BM” is
turned OFF or ON in
response to boom Broken harness be-
tween MC connector
mode select of switch Disconnect MC con- NO
operation A and solenoid valve
nector A and solenoid
SC.
valve SC. Connect
· Monitor item: Boom solenoid valve SC
mode selector. harness end con- NO Faulty MC.
nector terminals #1
YES and #2 with a clip.
Check for continuity
between harness end · Refer to T4-6-2.
connector A terminals Monitor boom
#7 and #8. mode control pres-
sure.
Faulty overload relief
YES Check if pressure
is 3.9 MPa (40 NO change valve in main
2
kgf/cm ). Exchange solenoid control valve, or faulty
YES valve unit SC and overload relief valve.
· Monitor item: boom solenoid valve unit
mode control valve out. SA.
· Boom mode selector Check if system
switch: ON operates properly.
Faulty solenoid valve
· Boom lower operation unit SC.
YES

Connector (Harness End Connector Viewed from the

Open End Side)
Boom Mode Selection MC Connector C Solenoid Valve Unit SC MC Connector A
Switch #10
#7 #8
C1 C10 A1 A11

C23 C31 A25 A32

T183-05-04-010
T183-05-04-101

T5-4-52
 TROUBLESHOOTING / Troubleshooting B
(Blank)

T5-4-53
 TROUBLESHOOTING / Troubleshooting B
F-7 When boom raise or arm roll-out is operated,
boom or arm starts to move after moving
slightly downward.

Related Fault Code: None

NO Damaged control valve

spool, broken spring, or
loose spool end.
Check if excessive
YES cylinder internal leak-
age is found.
Cylinder sealing failure.
Check if load check
YES
valve in control
valve is normal.
· Disassemble /
visual inspection Load check valve failure.
NO

NOTE: 1. During the initial stage of operation, oil

pressure and flow rate from the pump is
low. Therefore, if the load check valve is
malfunctioning, the oil in the bottom side (B)
of the boom cylinder flows back into the
circuit through the load check valve, When the load check
causing the boom cylinder to temporar- valve is faulty: (A)
ily retract.
2. Since oil pressure and flow rate from
the pump is low, if oil leaks from bottom
side (A) to rod side (B) due to faulty
boom cylinder piston or cylinder barrel,
the boom cylinder is temporarily re-
tracted during the initial stage of opera-
tion. In addition, cylinder force is re-
duced, increasing the cylinder drift in T105-07-04-012
this case.

T5-4-54
 TROUBLESHOOTING / Troubleshooting B
F-8 Front attachment drifts remarkably.

Related Fault Code: None

YES Pilot valve failure.

YES Cylinder sealing failure.

Check if cylinder
drift is reduced
when pilot shut-off YES Check if cylinder in-
valve is closed. ternal leakage is
found.
Control valve failure
Check if correspond- NO (sticking, etc.).
ing overload relief
NO pressure is normal.
· Refer to Operational
Performance Test Corresponding overload
section for pressure NO relief valve failure.
measurement pro-
cedure.

• Boom Cylinder Internal Leakage Check

1. With the bucket cylinder fully retracted and the

arm cylinder slightly extended from the fully re-
tracted position, lower the bucket tooth tips onto
the ground.

2. Disconnect hoses from the boom cylinder rod

side. Drain oil from the hoses and cylinders. (Plug
the disconnected hose ends.)
T105-07-04-009

3. Retract the arm cylinder to lift the bucket off the

ground. If oil flows out of the hose disconnected
pipe ends and the boom cylinders are retracted at
this time, oil leaks in the boom cylinders. In case
no oil flows out of the hose disconnected pipe
ends but the boom cylinders are retracted, oil
leaks in the control valve.

T5-4-55
 TROUBLESHOOTING / Troubleshooting B
F-9 During combined operation of front attach-
ment and swing, front attachment speed is
slow.

Related Fault Code: 14

• If other operations except the front/travel are nor-
mal, the pressure sensor (swing) seems to fail.

• Refer to the pages for Swing Horse Power Re-

ducing Control in the SYSTEM / Control System
group in the T/M (Operational Principle).
• If boom raise speed is slow only in combined op-
eration of swing and boom raise, swing prefer-
ence control might be failed. Refer to F-5.
• Check for loose harness connections beforehand.
NO

Check harness be-

tween MC connector C
(31P) harness end
YES each corresponding
terminal and pressure
Check if fault code sensor (swing) terminal
14 is displayed. #2 for breakage or short
circuit.
Disconnect pressure
sensor (swing). Check if Connector C Terminal:
NO voltage between har- #14: Pressure Sensor (Swing)
ness end connector
terminals #1 and #3 is
5±0.5 V. Check if voltage between
Check if fault code 14 · Key switch: ON pressure sensor (swing)
disappears after switch- harness end connector
ing pressure sensor terminal #1 and vehicle
(swing) with another NO frame matches specifica-
YES pressure sensor and re- tion.
trying. · Key switch: ON
· Specification: 5±0.5 V

YES
Connector (Harness End Connector Viewed from the Open End Side)

MC Connector C
#3

C1 C10

C23 C31
#14

Pressure Sensor (Swing)

1 2 3

T5-4-56
 TROUBLESHOOTING / Troubleshooting B

Find out cause of trouble by

tracing other trouble symp-
toms.

YES Faulty harness between MC

and pressure sensor (swing).

Faulty MC.
NO
· Refer to T4-6-2.

Broken harness between MC

YES and pressure sensor (swing)
terminal #3.

Broken harness between MC

and pressure sensor (swing)
NO terminal #1.

Faulty pressure sensor

(swing).

T5-4-57
 TROUBLESHOOTING / Troubleshooting B
SWING SYSTEM TROUBLESHOOTING
S-1 Swing is slow or unmoving.

Related Fault Code: None

• Check whether the pilot system is faulty or the

main circuit is faulty.
• In case other functions (front attachment and
travel) operate normally, the pilot pump is consid-
ered to be normal. If the pilot system is displaying
a problem, the cause of the trouble may exist in
the circuit after the pilot valve.
• In case the left travel speed is also slow, refer to
A-2.

Check if swing parking

YES brake release valve is
Check if swing parking scored or bound.
brake release pressure
YES is approx. 3.4 to 4.9
MPa (35 to 50
2
kgf/cm ).
· Relieve arm circuit. Faulty swing parking
· Monitor item: brake release spool in
Front attachment op- NO signal control valve.
eration
Monitor secondary · Possible to display with
pilot pressure. built-in diagnosing sys-
Check if secondary tem
pilot pressure is
normal.
· Specification:
Refer to OPERA-
TIONAL PER- NO Pilot valve failure.
FORMANCE TEST
Section. Disassemble, clean,
· Monitor item: and reassemble the
Swing control pilot
NO pilot valve. Check if the
pressure trouble still exists.
· Possible to display Faulty swing shuttle
with built-in diag- YES valve.
nosing system

T5-4-58
 TROUBLESHOOTING / Troubleshooting B

YES Faulty swing reduction

gear.

YES Check if swing motor

drain oil amount is
normal.
· Measurement: Faulty swing motor.
Refer to OPERA-
YES Check if swing relief NO
TIONAL PER-
pressure is normal.
FORMANCE TEST
· Relieve swing circuit. Section.
· Monitor item: Pump 2 de-
livery pressure Faulty swing relief
· Specification: valve.
Refer to OPERATIONAL NO
PERFORMANCE TEST
Section.

Faulty swing motor

NO parking brake release
valve.

T5-4-59
 TROUBLESHOOTING / Troubleshooting B
S-2 Swing is too fast

Related Fault Code: None

• Refer to F-5 (When doing combined operation of

swing and boom raise, boom raise speed is slow.)
or F-9 (During combined operation of front at-
tachment and swing, front attachment speed is
slow).
• If the swing speed is fast, the swing horse power
reducing control or swing preference control may
not function. This fault is that the swing pressure
sensor should be broken.
• Refer to the pages for Swing Horse Power Re-
ducing Control and Swing Preference Control in
the SYSTEM / Control System group in the T/M
(Operational Principle).

S-3 In the trenching mode, swing is slow in

combined operation of swing and boom
raise.

Related Fault Code: None

• The swing preference control may not function.

• Refer to the page for Swing Preference Control in
the SYSTEM / Control System group in the T/M
(Operational Principle).

Faulty work mode

NO switch (monitor) or bro-
ken harness between
MC and monitor.

Monitor work mode

switch.
Check if trenching Faulty MC.
NO
mode is selected.

· Monitor item: Work Monitor pressure from

· Refer to T4-6-2.
mode switch solenoid valve (Swing
· Work mode switch: Pressure).
Trenching mode YES Check if pressure is 0
MPa.
Faulty solenoid valve
· Monitor item: Swing / YES (swing preference).
boom control valve
out.

T5-4-60
 TROUBLESHOOTING / Troubleshooting B
TRAVEL SYSTEM TROUBLESHOOTING
T-1 Both right and left tracks do not rotate or
rotate slowly.

Related Fault Code: None

• Both right and left pilot valves, travel motors,

and/or control valve spools are unlikely to be
faulty at the same time.
• In case both travel systems do not operate, the
pilot system, which is applied to both side travel
motors, may be faulty. If the primary pilot pres-
sure is lower than specification, the front attach-
ment operating speed becomes slow as well.
Refer to A-1.
• In case the fast travel mode cannot be selected,
refer to T-4.
• If the power is insufficient, it seems that pressure
is not built up, check pressure sensor (travel) cir-
cuit, and refer to F-2.

T5-4-61
 TROUBLESHOOTING / Troubleshooting B
T-2 One side track doesn’t rotate or rotates
slowly. Machine mistracks.

Related Fault Code: None

• Check that both side track sags are equally ad-

justed.
• Faulty pump control will cause the machine to
mistrack. In this case, other trouble symptoms
such as slow bucket or swing single operation
speed, or slow arm roll-in and boom raise speed
in level crowd operation will occur at the same NO Check if travel motor
drain oil amount is nor-
time. If both mistrack and other symptoms as mal.
described above occurs at the same time, refer to · Measurement: Refer
A-2 and A-3. Check if symptom is to OPERATIONAL
• In one side track only doesn’t rotate, the pilot reversed when right PERFORMANCE
YES and left travel line TEST section.
valve, control valve, travel motor, or center joint hoses are switched
may be faulty. each other at the top of
center joint.
Check if travel relief
YES pressure in slow speed
side is normal. Bound control valve
· Relieve travel circuit. YES spool.
· Monitor item: Pump 1
and 2 delivery pressure
· Possible to display with Switch forward travel
Check if secondary built-in diagnosing sys- relief valve with reverse
travel pilot pressure tem travel one, or right travel
is normal. · Measurement: relief valve with left one.
Refer to OPERATIONAL NO Check if symptom is re-
Monitor item: PERFORMANCE TEST versed.
Travel control pilot section.
pressure
Faulty pilot valve.
NO
Relationship between Faulty Seal Location
and Mistrack Direction Seal Location
Seal When pivot turn is
When traveling straight
NO. performed
1 External Oil Leak ←
Pi (Travel Speed Change)
2 ←
Oil Leak
1

3 2
3

4
Right Travel
(Reverse)
5 Left Travel 4
(Reverse) 5
Right Travel
6 (Forward)
Left Travel
(Forward) 6
7
7
and External oil leak and External Leak
T16J-03-07-001

T5-4-62
 TROUBLESHOOTING / Troubleshooting B

NO Faulty travel motor.

NO Faulty travel reduction

Disassemble and clean gear.
travel motor swash an-
YES
gle control mechanism.
Check if any abnormal-
Disassemble and ity is found. Faulty travel motor
clean travel motor swash angle control
YES mechanism.
counterbalance valve.
YES
Check if same symp-
tom occurs. Faulty counterbalance
NO valve.

NO Faulty center joint.

Faulty travel relief

YES valve.

Arrangement of Pipe Line

Front

2
1
3
4

M162-07-071

1 - Left Travel (Forward) 3 - Right Travel (Reverse) 5 - Pilot (Travel Speed Change) 6 - Drain
2 - Right Travel (Forward) 4 - Left Travel (Reverse)

T5-4-63
 TROUBLESHOOTING / Troubleshooting B
T-3 Machine mistracks during travel and front
attachment combined operation.

Related Fault Code: None

Faulty flow combiner
Disconnect hose (SL), YES valve control spool in
connecting to flow signal pressure con-
combiner valve, from trol valve.
signal control valve.
NO
Install pressure gauge
to signal control valve. YES Faulty load check
Check if signal pres- Check check valve for valve.
sure is approx. 3.9 any abnormality.
Check flow com- MPa (40 kgf/cm ).
2
NO Find out cause of
biner valve in con-
trol valve for any trouble by tracing
NO other trouble symp-
abnormality.
toms.

Faulty flow combiner

YES valve.

Signal Control Valve

SL Port

T16J-03-06-001
(Control Valve Side)

T5-4-64
 TROUBLESHOOTING / Troubleshooting B
(Blank)

T5-4-65
 TROUBLESHOOTING / Troubleshooting B
T-4 Fast travel is inoperable.
Travel mode doesn’t change from slow
mode to fast mode.

Related Fault Code: None

• Refer to the pages for the Travel Motor Swash

Angle Control in the SYSTEM / Control section in
the T/M (Operational Principle).
• Check for loose harness connections beforehand.
NO Faulty travel mode switch or
broken harness between
travel mode switch and MC.

Monitor travel mode Check if symptom is re-

switch. Check if dis- versed when pressure
NO
played indication is sensor (travel) is switched
highlighted in response with another pressure sen-
to travel mode switch sor.
operation.
· Monitor item: Travel
mode Monitor pressure sen-
sor (travel). Check if
pressure varies in re-
YES sponse to travel lever
operation.
· Monitor item: Travel lever Disconnect solenoid
stroke valve unit (SB). Check if
voltage at solenoid valve
Monitor travel motor Speed NO unit (SB) harness end
Control Pressure. connector terminal #1 is
Check if pressure is 3.9 24 V.
2
MPa (40 kgf/cm ).
· Travel mode: Fast
YES · Monitor item:
Travel motor control valve
out
· Travel mode: Fast
YES

T5-4-66
 TROUBLESHOOTING / Troubleshooting B

YES Faulty pressure sensor

(travel).

Broken harness between

travel pressure sensor and
MC or clogged shuttle
NO valve in signal pressure
control valve.

YES Faulty solenoid valve unit

(SB).
Exchange solenoid
YES valve unit (SB) with so-
lenoid valve (SA). YES Faulty travel motor swash
Check if Fast travel is Check if travel motor angle control mechanism.
operable. swash angle control
mechanism is bound or
NO scored. Faulty travel motor or travel
reduction gear.
NO

Broken harness between

NO solenoid valve and MC.

Faulty MC.

· Refer to T4-6-2.

Connector (Harness End Connector Viewed from the open End Side)
Solenoid Valve Unit (SB)

T183-05-04-010

T5-4-67
 TROUBLESHOOTING / Troubleshooting B
OTHER SYSTEM TROUBLESHOOTING
O-1 Wiper is inoperable or not retracted.

Related Fault Code: None

• The wiper is driven by electric power routed via

the relay circuit controlled by the monitor assem-
bly. In case the wiper is inoperable, first check the
wiper motor and links for any abnormality using
an auxiliary electric power and the test harness.
• If the front window is open, the wiper won’t oper-
ate. Check that the front window is securely
closed.

Faulty front window

open/close switch or
YES
short-circuited harness
between front window
open/close switch and
monitor.
Disconnect front
window open / close YES Faulty wiper relay.
Remove test harness
switch. Check if and reconnect circuit to
wiper operate. YES the original position.
Connect test harness
· Key switch: ON (ST 7227) between Replace wiper relay
auxiliary electric one at a time to see if
power (fuse box #19) wiper operates. To A
NO
and wiper motor as 動く ON
· Key switch:
NO
illustrated to the right.
Check if wiper oper- Faulty wiper motor or
ate. links.
NO or test har-
· Key switch: ON ness lamp doesn’t
light normally.
NOTE: When the wiper motor
is normal, lamp S lights
while the wiper is mov-
ing within the operating
range. Both lamps B YES End (Faulty monitor).
and S light for a mo-
ment at the same time Replace monitor as-
only when the wiper A sembly to see if wiper
reaches the intermittent operates.
stop position. Faulty cab harness.
NO

T5-4-68
 TROUBLESHOOTING / Troubleshooting B

Test Harness Application Circuit

Fuse Box #12

Lamp S
M B S

Lamp B Wiper Motor

L E
Ground

T178-05-04-004

Wiper Operating Range Intermittent Stop Position

Retracted Position

Operating Range

T178-05-04-005

Test Harness Connection Method

Wiper Motor Lamp B

Lamp S

Test Harness Fuse Box

T157-07-04-004

T5-4-69
 TROUBLESHOOTING / Troubleshooting B
O-2 Malfunction of counterweight removal de-
vice.

Related Fault Code: None

• Refer to the page for Pump Control in Counter-

weight Removal Operation in the SYSTEM / Con-
trol System group in the T/M (Operational Princi-
ple).
• Check for loose harness connections beforehand.

YES Faulty pressure sensor

(counterweight removal).
Exchange pressure
sensor (counter-
Broken harness between
NO weight removal) with Disconnect pressure pressure sensor (coun-
other pressure sen- sensor (counterweight NO terweight removal) ter-
sor. removal). minal #1 and MC or faulty
Check if system op- Check if pressure sen- MC.
Monitor pressure sen- erates properly. sor (counterweight)
sor (counterweight re- harness side connector
moval) terminal #1 is 5 ± 0.5 V. Disconnect MC connec-
Check if pressure is tor C.
approx. 3.9 MPa (40 · Key switch: ON Connect MC Connector
2 YES C terminal #23 to frame.
kgf/cm ).
Check for continuity be-
· Monitor item: Coun- tween pressure sensor
terweight removal (counterweight removal)
· Operate counter- harness side connector
weight removal pilot #1 and #3.
valve.

Refer to F-2 Malfunction

YES of precision mode.

Connector (Harness End Connector Viewed from the Open End Side)

MC Connector C
Pressure Sensor (Counterweight removal)

C1 C10

1 2 3
C23 C31

T5-4-70
 TROUBLESHOOTING / Troubleshooting B

YES Faulty counterweight re-

moval pilot valve.

Broken harness between

pressure sensor (coun-
NO terweight) terminal #1 or
#3 and MC.

T5-4-71
 TROUBLESHOOTING / Troubleshooting B
O-3 Malfunction of auto-lubrication system.

• Auto-lubrication can not be made even when auto

lubrication switch is ON.
• Check for loose harness connections beforehand.
• Intervals-90 minutes (Adjustable from 10 to 90 Faulty auto-lubrication
NO switch or broken har-
minutes), lubricating time-5 minutes. ness between
Disconnect MC connector C.
YES Check continuity between MC auto-lubrication switch
connector C harness end con- and ground.
nector terminal #8 and frame.
· Auto-lubrication switch: ON Faulty MC.
YES
Exchange auto-lubrication · Refer to T4-6-2.
normal rotation relay with
auto-lubrication reverse rota-
Check if
tion relay.
NO auto-lubrication Check if auto-lubrication sys-
indicator is YES
tem works. Faulty auto lubrication
turned on. normal / reverse rota-
Or, auto-lubrication reverse
rotation relay harness end tion relay.
connector terminal #3 is Disconnect MC
NO grounded. connector A and
Disconnect pres- Check if auto-lubrication sys- power transistor. Broken harness be-
NO
sure switch. tem works. Connect MC con- tween power transistor
Check if Or, after exchanging nector A harness terminal #7 and MC.
auto-lubrication auto-lubrication normal rotation end connector ter-
system works. relay with auto-lubrication re- minal #30 and #31
verse rotation relay, NO with a clip.
auto-lubrication reverse rota- Check continuity A
tion relay harness end con- between power
nector terminal #3 is grounded. transistor terminal
Check if auto-lubrication sys- #7 and #6.
tem works.
Faulty pressure sensor.
YES
Broken harness be-
YES tween power transistor
terminal #3 and auto
lubrication normal rota-
Disconnect tion relay terminal #1.
auto-lubrication nor-
mal rotation relay. Broken harness be-
Connect tween power transistor
auto-lubrication nor- NO
Check if voltage at terminal #5and ground
A power transistor mal rotation relay or, broken harness be-
terminal #3 is 24 V. harness end connec- tween power transistor
tor terminal #2 and terminal #4 and
· Key switch: ON ground with a clip. auto-lubrication normal
NO
Check continuity be- rotation relay terminal
tween frame and ter- #2, or, broken harness
minal #5, 2 or 6. between power transis-
Check continuity be- tor terminal #2and
Connector (Harness End Connector Viewed from the YES tween auto-lubrication d
NO
Open End Side) normal rotation relay Faulty auto-lubrication
terminal #3 and frame. device, or broken har-
MC Connector C MC Connector A ness between auto lu-
#8 brication normal reverse
C1 C10 A1 A11 rotation relay and
auto-lubrication device.

Faulty power ransistor.

YES
C23 C31 A25 A32
#30 #31

T5-4-72
 TROUBLESHOOTING / Troubleshooting B
• Auto-lubrication system can not stop even after the
lapse of lubrication time.
• Interval: 60 minutes (Adjustable from 10 to 90
minutes), lubrication time-5 minutes.
YES Faulty auto-lubrication
Exchange normal rotation relay.
auto-lubrication
normal rotation relay YES Faulty MC.
with auto-lubrication
reverse rotation re-
lay.
Check if
auto-lubrication Check if voltage at
system stops. power transistor ter- YES Short-circuited har-
NO minal #7 is 5 V. Disconnect power ness between
transistor. auto-lubrication nor-
· Key switch: ON Check continuity be- mal rotation relay ter-
tween auto-lubrication minal #2 and power
normal rotation relay transistor terminal #4.
NO harness end connector
terminal #2 and frame.
Faulty power transis-
NO tor.

• Auto-lubrication system can not stop even after turn-

ing off the auto-lubrication switch.

• Refer to “Auto-lubrication system can not stop

even after the lapse of lubrication time.”
• Interval: 60 minutes (Adjustable from 10 to 90
minutes), lubrication time-5 minutes. Faulty MC or refer to
YES “Auto-lubrication system
can not stop even after
lapse of lubrication time.”

Check if
auto-lubrication indi-
cator is turned on.
Faulty lubrication switch,
or short-circuited harness
NO between MC and
auto-lubrication switch.

• There is a possibility that the pressure cannot be in-

creased to the required level within the set time. In
this case, check the following:

• Grease amount in cartridge

• Air mixed into circuit
• Plug at cartridge
• Failure of pressure switch (limit switch)

T5-4-73
 TROUBLESHOOTING / Troubleshooting B
Greasing into Piping

• Greasing into piping between the distribution valve • Greasing into supply piping (ranging from grease
and lubricating points pump to the distribution valve on arm) for five min-
utes.
• Piping between the distribution valve on boom 1. Disconnect hose (2) from the grease pump and
and lubricating points: remove the plug from supply port (3) of the dis-
1. Open discharge ports at the top of the distribution tribution valve on the frame.
valve on the boom to the atmosphere. (Do not 2. Attach a grease nipple to supply port (1) of the
attach plugs.) distribution valve on arm, and grease into it.
2. Grease into nipples at the centralized greasing 3. Plug hose (2) and or supply port (3) whichever
block for boom. grease comes out first, continue to grease until
3. Seal the ports with plugs when grease comes out grease comes out from the unpluged end or port.
from discharge ports of the distribution valve on 4. After confirming that grease comes out from the
the boom. end or port, connect hose (2) to the grease pump,
4. Continue to grease into nipples at the centralized and install the plug on supply port (3).
greasing block until lubricating points are filled
fully with grease.
1
• Piping between the distribution valve on the frame
and boom cylinder bottom side: Arm
Grease into discharge ports at the top of the
distribution valve on the frame, and confirm that
the boom cylinder bottom side is filled fully with
grease. Boom

• Piping between distribution valve on arm and

lubricating points:
1. Open discharge ports at the top of the distribution
valve on the arm to the atmosphere. (Do not at-
tach plugs.) 2 Frame
2. Grease into nipples at the centralized greasing
block for arm.
3. Seal the ports with plugs when grease comes out 3
from discharge ports of the distribution valve on
arm. T17V-05-04-003

4. Continue to grease into nipples at the centralized

greasing block until lubricating points are filled • Greasing into Grease Pump
fully with grease. 1. Confirm that a grease cartridge is provided inside
the grease pump.
2. Remove an air vent screw from the grease pump.
3. Turn on the auto lubrication switch at the rear of
the cab, and turn on the key switch to start the
grease pump.
4. Replace the air vent screw when grease comes
out from the air vent port.
(Normally, grease comes out within10 seconds.)
5. Turn off the key switch.

T5-4-74
 TROUBLESHOOTING / Troubleshooting B
O-4 Malfunction of Air Conditioner

The air conditioner has a self-diagnosis function.

The self-diagnosis functions to:
1) Display Fault Codes
2) Change Displayed Fault Codes
3) Delete Fault Code
4) End Fault Code Display

• Display Fault Code

1. Press the fan OFF switch to turn the fan OFF.
2. Press and hold both the upper and lower sides of
the temperature control switch on the air condi-
tioner control panel at the same time for more Temperature
than 3 seconds with the key switch ON. Fan OFF Switch Control Switch

NOTE: After operation has been performed, the

buzzer will sound.

3. If any fault codes are found, the LCD displays the

fault codes as E{{.
NOTE: If more than one fault code is found, the
lower number fault code will be displayed M178-01-017
LCD
first.

Fault Code List

Fault
Location in Trouble Cause Symptom
Code
Abnormal circulation E11 Broken circuit in air circulation Y value (air flow-in temperature) cannot be
air sensor sensor adjusted in response to the
E12 Short-circuited circulation air set-temperature.
sensor
Abnormal fresh air E13 Broken circuit in fresh air sensor Operation is controlled under such cir-
sensor E14 Short-circuited fresh air sensor cumstance as no fresh air sensor is pro-
vided.
Abnormal solar E18 Short-circuited solar radiation Operation is controlled under such cir-
radiation sensor sensor cumstance as no solar radiation sensor is
provided.
Abnormal evapora- E21 Broken circuit in evaporator sen- Operation is controlled under such cir-
tor sensor sor cumstance as the evaporator temperature
E22 Short-circuited evaporator sen- is set to 10 °C (50 °F).
sor
Abnormal damper E43 Abnormal air vent damper Corresponding damper servo becomes
E44 Abnormal air mix damper inoperable.
E45 Abnormal circulation/fresh air
damper
Water temperature E15 Broken circuit in water tempera- Operation is controlled under such cir-
sensor ture sensor cumstance as the water temperature is set
E16 Short-circuited water tempera- to 60 °C (140 °F). (Warm-up control is not
ture sensor performed.)
Abnormal refrigerant E51 Abnormal high/low refrigerant The compressor clutch is disengaged.
pressure (The compressor stops.)

T5-4-75
 TROUBLESHOOTING / Troubleshooting B
• Change Displayed Fault Code
When displaying more than one fault code, press Temperature
either the upper or bottom side of the temperature Control Switch
control switch key. The following fault code is dis-
played.
NOTE: Each time the displayed fault code is
changed, the buzzer sounds. In case only
one fault code exists, the displayed fault
code remains unchanged.
M178-01-017
LCD

• Delete Fault Code

LCD
1. Press and hold both the circulation air switch and
the fresh air switch for more than 3 seconds at
the same time to delete the fault code.
NOTE: After the fault code is deleted, the buzzer
will sound.

2. After the fault code has been deleted, the LCD

displays E{{. M178-01-017
Circulation Fresh Air
Air Switch Switch

Fan OFF Switch

• End Fault Code Display

Press the fan OFF switch, or press the upper side of
the fan switch key. The self-diagnostic mode is com-
plete.

M178-01-017
Fan Switch

T5-4-76
 TROUBLESHOOTING / Troubleshooting B
※ Please fill in all sections and return this AIR CONDITIONER
TROUBLE REPORT to Hitachi Tsuchiura Works Quality Assurance
Dept. after experiencing a problem with your machine’s air condi-
tioning system.

< AIR CONDITIONER TROUBLE REPORT > File No.

(1) What Checked by:
Model (Serial No. )
Operation Type Manual Semi-Auto Full-Auto
Delivery Date Year Month
(2) When
Date Year Month Day Operating Hour ( h)
Time Morning Daytime Evening Night
Frequency Every Day Once a Week Once a Month Times per
(3) Where
Job Site Address State County Town
Access Road Condition Paved Not Paved (Gravel Sand Soil)
(4) How (Operating Conditions)
Weather Fine Cloudy Rain Snow
Atmospheric Temperature Very Hot Hot Cold Very Cold
Operating Conditions Parking Traveling Working
Temperature Control Paint blanks equal to red indicators. / Fill in set-temperature when
full-auto operation
A/C ON OFF
Control Air Induction Re-Circulation Fresh Air Circulation
Panel AUTO ON OFF Not Available
Fill following items when operated in manual mode or when manual control type unit is used.
Vent Position Front Front / Rear Foot Front / Rear and Foot
Fan First Second Third Fourth Fifth Sixth
(5) How (Problem Symptom)
Abnormal Compressor Operation
Symptom Not turned ON <Check Result>
Not turned OFF (1) Is problem reproducible ?
Others Reproducible
Uncontrollable air temperature Not reproducible
Symptom No cool air (2) Pressure (To be measured at gauge manifold)
No warm air Low Pressure
Others High Pressure
Uncontrollable air volume (3) Which parts have been replaced ?
Symptom Air flows in Hi mode only 1
No air flows
2
Small air volume
Others
Uncontrollable vent hole ∗ Before replacing the control amplifier, be sure to
Symptom Vent hole isn’t selected check that the connectors are correctly connected
while repeatedly disconnecting and reconnecting
Others
connectors.
Abnormal panel indication
Faulty Indica- Vent Hole
tor A/C
AUTO
Fresh Air Circulation
Fan OFF
Fan (Lo • •• Hi)
Temperature Control
Symptom Stays OFF
Stays ON
Blinks
Others

T5-4-77
 TROUBLESHOOTING / Troubleshooting B
Cooling Circuit

Refrigerant pressure Piping and/or parts are stained with

in both high and low Bubbles can be seen in sight oil, respond to gas detector.
pressure sides is low. glass.
No oil stain is found or gas detector
doesn’t respond. Refrigerant has not
been refilled for longer than one sea-
son.
No bubbles are seen in sight
glass.

After cooling at fast speed continu-

ously, cooling power is reduced. Air
flow volume remains unchanged.

Air flow volume is reduced.

Refrigerant pres-
sure in low pressure Bubbles can be seen in sight Compressor cylinder is extremely hot,
side is high. glass. emitting a smell.
Insufficient
Cooling
Power Refrigerant pressure in high Compressor cylinder is extremely hot,
pressure side is low. emitting a smell.

Heater unit emits hot air.

Refrigerant pres- Bubbles can be seen in sight Refrigerant pressure in low pressure
sure in high pres- glass. side is low.
sure side is high.
Condenser is stained and clogged.

Even if condenser is sprayed with water, few bubbles appear. Receiver dryer tem-
perature is low.

After cooling at fast speed continu-

ously, cooling power is reduced. Air Frost Thermistor doesn’t cool.
flow volume is reduced. forms.
Thermistor cools.

T5-4-78
 TROUBLESHOOTING / Troubleshooting B

Gas leaks from pipe joints and/or parts. Re-tighten or replace parts.

Normal leakage of refrigerant from hoses. Refill refrigerant.

Improper adjustment (excessive restriction) of Readjust or replace expansion valve.

expansion valve.
Remove clog, or replace receiver and/or expan-
Clogged expansion valve. sion valve.

Clogged low pressure circuit and/or evaporator. Remove clog, or replace parts.

Frozen expansion valve or water in circuit. After evacuation, refill refrigerant and/or replace
receiver dryer.
Gas leaks from case.
Seal gaps using vinyl tape or packing compound.

Poor contact of expansion valve temperature Make good contact. Replace temperature sensing
sensing cylinder. stay.
Improper adjustment (excessive open) of expan-
Readjust or replace.
sion valve.

Insufficient compressor discharge (faulty gasket Replace.

and/or valve).

Improper water stop valve wire adjustment and/or Check and readjust or replace.
faulty stop valve.
Repair.
Poor airtight fitting of outside air damper (outside
air induction type).

Remove clog, or replace parts.

Clogged high pressure circuit before receiver
dryer.
Clean Condenser.

Excessive refrigerant. Remove excessive refrigerant to proper level.

After evacuation, refill refrigerant and/or replace

Air is mixed in system. receiver dryer.

Incorrect thermistor location. Correct thermister location.

Gas leaks from case. Seal gaps using vinyl tape or packing compound.

Faulty thermistor (stays ON). Disconnected thermister cord.

Even if function and performance are normal, Instruct user on correct air-conditioner operation.
when air-conditioner is kept operated for a long (Reset thermistor to either minimum or middle
time with thermistor in max. cooling position and cooling position or increase air flow.)
air flow in M or L mode, frost may form.

T5-4-79
 TROUBLESHOOTING / Troubleshooting B
Cooling Circuit

Case connection. Louver resonance.

Fan contacts case, or foreign matter enters case.

Blower fan connection.
Brush friction noise, metal and/or thrust washer con-
tact noise.

Gas blowing sound (roaring). Gas vibration noise (compressor discharge and/or
suction gas noise).

Expansion valve connection, whistle Abnormal noise from expansion valve (Expansion
Noise sound, gas blowing sound. valve is normally functioning.).

Faulty clutch bearing, and/or idle pulley bearing.

Clutch disengaging sound.

Contact of clutch amature due to resonance, or loose
belt and/or screws.

Noisy compressor.
Compressor rotating sound.
Vibration and/or loose screws due to excessive drive
belt looseness.

Broken heater core and/or hose.

Water leak and/or splash.
Clogged case drain port and/or drain hose.
Others

Absorbed cigarette and dust smell on evaporator fins.

Abnormal smell.

T5-4-80
TROUBLESHOOTING / Troubleshooting B

Repair or replace.

Remove foreign matter. Readjust fan motor location.

Slight noise is unavoidable.

Replace if loud.

No functional problem exists.

Provide silencer if intolerable.

Replace expansion valve if whistle sound is heard. Gas flow noise can be slightly heard.

Replace.

Repair or replace clutch. Re-tighten screws.

Repair or replace.

Re-adjust drive belt.

Replace.

Clean.

-1
Clean evaporator. When humidity is high, open door. While rotating fan at approx. 1500 min in
L mode for more than 10 minutes, flush smell out by condensed water.

T5-4-81
 TROUBLESHOOTING / Troubleshooting B
Compressor

Compressor doesn’t rotate. Clutch terminal voltage is normal 24 V.

Inoperable Clutch terminal voltage is low.

cooling
system.
Clutch terminal voltage is 0 V.

Bubbles exist even after refrigerant is refilled.

Check for oil and refrigerant leaks from parts other than
Both high and low side
compressor and pipe joints using gas detector.
pressures are low.

Both com-
pressor
and blower
motor ro- Check for oil and
tate. refrigerant leaks
from compressor Refer to NOTE 1 and 2 on page T5-4-85.
(no leaks from
Refrigerant has not been refilled for longer
parts other than
than one season.
compressor) using
gas detector.
Stain Refrigerant is discharged within 1 to 2
on months after being recharged. Check for
exterior. refrigerant leaks using gas detector.

Refrigerant is kept charged for longer than

2 years.

Compressor cylinder is not hot. (Refrigerant returns to com-

High pressure side is pressor in liquid form.)
slightly low and low pres-
sure side is high. No refrigerant returns in liquid form. High pressure side is low.
Bubbles can be seen through
Others
sight glass.

High pressure side is high.

Refer to the Cooling Circuit Troubleshoot-
ing Table on page T5-4-78.
Temperature is not cooled when compressor is
operated at fast speed continuously.

Air flow from blower is insufficient.

Compressor rotation is abnormally draggy.

Overheating
is susceptible
to occur.

Trouble other than compressor. Refer to the Cooling Circuit Troubleshooting Table on page
T5-4-78.

T5-4-82
TROUBLESHOOTING / Troubleshooting B

Seized clutch. Replace.

Improper gap between amature and rotor (improper air gap).

Replace.
Broken or short-circuited core cable.

Shaft doesn’t rotate (internally locked). Replace.

Faulty Electrical System.

Faulty Electrical System.

Faulty mechanical seal, gasket, and/or charge valve.

Replace.
Oil leaks from oil plug.

Oil and refrigerant leaks from front housing, and/or cylinder block joint. Replace.

Normal leaks from hoses. Charge

refrigerant.

No leaks (normal).

Refer to the Cooling Circuit Troubleshooting Table on page T5-4-78.

Broken valve (See NOTE 3 on page T5-4-85.)

Replace.
Blown gasket (See NOTE 3 on page T5-4-85.)

Check and
Excessive oil.
adjust oil level.

Broken clutch bearing due to overly tightened belt. Replace.

Shaft doesn’t rotate.

Replace.
Shaft rotates draggy.

T5-4-83
 TROUBLESHOOTING / Troubleshooting B
Compressor

Noise is heard when clutch is OFF.

Abnormal
noise

Noise is heard when clutch is ON.

T5-4-84
 TROUBLESHOOTING / Troubleshooting B

Broken clutch bearing.

Replace.
Contact or slip due to poor air gap.

Faulty idle pulley bearing.

Saggy belt. Refer to the Cooling Circuit

Troubleshooting Table on
page T5-4-78.
Loose screws.

Broken valve.
Replace.
Blown gasket.

Abnormal internal noise. Replace.

Vibration due to saggy belt.

Refer to the Cooling Circuit
Loose screws. Troubleshooting Table on
page T5-4-78.

NOTE:
1. Don’t quickly decide that oil is leaking when a stain around the clutch and/or gasket is found. A
slight oil seepage will appear due to the seal construction. However, this oil seepage will not
cause malfunction. Be sure to accurately check whether oil is leaking or seeping only.
2. When gas detector is used in the high sensitivity range, normal gas leaks from rubber hose sur-
face may be detected. As long as the specified rubber hoses are used, the problem should not
occur. (In case a large leaks is detected, the hose may be broken.)
3. After allowing the compressor to idle for 10 to 15 minutes, normal pressure difference between
2
high pressure side and low pressure side is 0.49 MPa (5 kgf/cm ) or less. When the clutch is
turned OFF, the pressure difference between high pressure side and low pressure side will
disappear within about 10 seconds.

T5-4-85
 TROUBLESHOOTING / Troubleshooting B
Work After Replacing Components

The following work is required after replacing

compressor, high pressure hose, low pressure hose,
condenser, receiver tank, liquid hose, and air
conditioner unit.
The same work is required when gas leakage is
found.

1. Add compressor oil

2. Charge air conditioner with refrigerant

• Purging
• Charge air conditioner with refrigerant
• Warm up operation
• Inspection

Add Compressor Oil

Compressor oil quantity to be added after component

3
replacement: 180 cm (0.19 qt)

T5-4-86
 TROUBLESHOOTING / Troubleshooting B
CHARGE AIR CONDITIONER WITH
REFRIGERANT
Necessity of Purging
Be sure to purge the air conditioner circuit with a
vacuum before charging with refrigerant (R134a)
because the following problems can arise if air or
other gases remain in the A/C circuit.

1. Pressure rise in the high pressure side

Air
If air remains in the air conditioner circuit, this
disturbs the heat exchange between refrigerant
and air in the condenser, causing pressure to rise
in the high pressure side (compressor side).
Usually, refrigerant gas is easily liquefied;
however, air cannot be liquefied and remains as a
gas in the condenser because the temperature at
which air liquefies is extremely low. That is,
liquidation of the refrigerant gas in the condenser
decreases by the amount of air in the circuit, and Pressure increases if air
W115-02-10-001
the gas pressure in the high pressure side remains in the air
conditioner circuit
increases accordingly.

2. Metal corrosion

If air remains in the air conditioner circuit, a

chemical reaction between refrigerant and
moisture in the air takes place, and as a result,
hydrochloric acid, that corrodes metals such as
aluminum, copper and iron, is produced.

Hydrochloric acid Hydrochloric acid W115-02-10-002

corrodes metals if
moisture exists

Metal corrosion

3. Plugging of the expansion valve by moisture

When high pressure refrigerant gas passes

through the expansion valve, gas pressure
decreases and temperature drops. Moisture
included in high pressure refrigerant gas in the air
conditioner circuit freezes at the expansion valve
orifice, plugging refrigerant flow. Operation of the Plugged refrigerant
air conditioner becomes unstable and cooling Ice produced at the
flow
efficiency lowers. expansion valve disturbs
W115-02-10-003
refrigerant flow, lowering
cooling efficiency
Low cooling
efficiency

T5-4-87
 TROUBLESHOOTING / Troubleshooting B
Purging Procedure Gauge Manifold
1. Close the high and low pressure valves on the
gauge manifold (Parts Number 4360564). Low Pressure
Connect the high-pressure-side charge hose and Valve
the low-pressure-side charge hoses to the Low Pressure
Charge Hose High Pressure
high-pressure-side charge valve (“D” marked)
Valve
and to the low-pressure-side charge valve (“S”
marked) located on the compressor, respectively. High Pressure
Connect the charge hose located on the center of Charge Hose
the manifold bottom to the vacuum pump (Parts Center Pressure
Number 4360565). Charge Hose
Vacuum Pump

NOTE: Vacuum Pump Joint Adapter (Parts

Number 4360566).

IMPORTANT: Never mistake the charge hose

connections.

W115-02-10-005

Low Pressure
Side S
Compressor
D
High Pressure
Side
T142-02-05-018

Fully Open
2. Open the high pressure and low pressure valves
in the gauge manifold. Perform purging for 10
minutes or more by operating the vacuum pump. Fully Open

In Operation

W115-02-10-005

T5-4-88
 TROUBLESHOOTING / Troubleshooting B
3. When the low pressure gauge reading falls
below-755 mmHg, stop the vacuum pump and
close the high and low pressure valves. Wait for Close
approximately five minutes and confirm that the
pointer does not return to 0. Close

IMPORTANT: If the pointer returns to 0, retighten

the line connections and perform
purging again.

In Operation

W115-02-10-005

4. With the high pressure and low pressure valves

of the gauge manifold closed, connect the charge
hose to the refrigerant container (Parts Number
4347644).

Refrigerant
Container

W115-02-10-007

5. Loosen the charge hose connection to the gauge

manifold and open the refrigerant container valve
to purge air in the charge hose with the refrigerant
pressure. Loosen

Open

W115-02-10-007

T5-4-89
 TROUBLESHOOTING / Troubleshooting B
6. Fully tighten the charge hose connection to the
High
gauge manifold. Open the high pressure valve Pressure
and refrigerant container valve to charge with Gauge
refrigerant (R134a). Tighten
Close the high pressure valve and refrigerant
container valve when the high pressure gauge
2 Open
reading reaches 98 kPa (1 kgf/cm , 14 psi).

NOTE: Use warm water of 40 °C (104 °F) or less

to warm the refrigerant container to aid in
charging operation.
Open

IMPORTANT: Always stop the engine when

charging the air conditioner with
refrigerant. Never position the
refrigerant container upside down
during charging operation. When
changing the refrigerant container
during charging operation, be sure W115-02-10-007
to purge air from the charge hose,
as shown in step 10.

7. After charging, check the line connections for gas W115-02-10-008

leaks using leak tester (Parts Number 4360567).

IMPORTANT: Use the leak tester for R134a.

T5-4-90
 TROUBLESHOOTING / Troubleshooting B
8. Confirm that the high pressure and low pressure
valves in the gauge manifold and the refrigerant
container valve are closed.
Start the engine and operate the air conditioner.

Operating Conditions of the Air Conditioner:

Engine Speed : Slow Idle
Cab Window : Fully Open
Cooler Switch : ON
Airflow Volume : Maximum
Thermo Switch : Maximum

9. Open the low pressure valve in the gauge

manifold and the refrigerant container valve to
charge with refrigerant until the bubbles seen in
the receiver/drier sight glass disappear. Open

NOTE: The required refrigerant quantity is 1100

g±50 g (2.5±0.01 lb).

IMPORTANT: Never open the high pressure valve

in the gauge manifold.

Open

10. If the refrigerant container becomes empty during

the charging work, replace it with a new W115-02-10-007

refrigerant container as follows:

(1) Close the high pressure and low pressure Close
valves on the manifold gauge.
(2) Replace the empty container with a new one.
(3) Tighten, then slightly loosen the refrigerant
container joint.
(4) Slightly open the low pressure valve on the
manifold gauge.
(5) When the refrigerant container joint starts to
leak, immediately tighten the refrigerant
container joint and close the low pressure Close
valve on the manifold gauge.

11. After charging, close the low pressure valve in the

gauge manifold and the refrigerant container
valve, and stop the engine.

W115-02-10-007

T5-4-91
 TROUBLESHOOTING / Troubleshooting B
12. Start the engine and operate the air-conditioner
again.
Observe the sight glass of the receiver/drier to
check refrigerant quantity.
Operating Conditions of the Air Conditioner:
Engine Speed : Slow Idle
Cab Window : Fully Open Sight Glass
Cooler Switch : ON
Airflow Volume : Maximum
Thermo Switch : Maximum
IMPORTANT: If the air conditioner is operated
with very low refrigerant, a bad load
will be exerted on the compressor. If
the air conditioner is overcharged
Receiver/Drier
with refrigerant, cooling efficiency
will lower and abnormal high
pressure will arise in the air
conditioner circuit, causing danger.
NOTE: As the bubbles in the sight glass vary
W115-02-10-009
depending on the ambient temperature,
check refrigerant quantity confirming the
changes in pressure .

Checking procedures: Stop the air conditioner and

wait until refrigerant returns to the balanced pressure.
Then, start the air conditioner again.
Relation between Refrigerant Quantity and Refrigerant
Flow in Sight Glass:
Refrigerant Flow in Sight Glass
Refrigerant
(approx. 1 min. after air conditioner Explanation for Refrigerant Flow in Sight Glass
Quantity
switch is turned ON)
(immediately after) (approx. 1 mm after) Immediately after the air conditioner is turned ON, few
Adequate bubbles are seen. Then the flow becomes transparent
and shows thin milk white color.
W115-02-10-016

No bubbles are seen after the air conditioner is turned

Overcharged ON.
W115-02-10-017

Bubbles are seen continuously after the air condi-

Not Enough tioner is turned ON.
W115-02-10-018

CAUTION: Wait until the high-pressure-side

W115-02-10-019
pressure drops to less than 980 kPa (10
Bubbles exist: Bubbles are seen in refrigerant flow as 2
kgf/cm , 142 psi) before attempting to dis-
both liquid refrigerant and refrigerant gas exist, being
connect the high-pressure-side charge hose.
mixed.
Otherwise, refrigerant and compressor oil
may spout.
W115-02-10-020
Transparent: Refrigerant flow is transparent as only
liquid refrigerant exists. 13. After checking refrigerant quantity, disconnect the
low-pressure-side charge hose first. Wait for the
high-pressure-side pressure to drop to less than
2
980 kPa (10 kgf/cm , 142 psi). Disconnect the
115-02-10-021
high-pressure-side charge hose.
Milk white: Refrigerant flow shows thin milk white
as oil and refrigerant are separated.

T5-4-92
 TROUBLESHOOTING / Troubleshooting B
Warm-up Operation
After charting the air conditioner, carry out warm-up
operation five minute to lubricate system with
compressor oil.

Operating Conditions of the Air Conditioner

Engine Speed : Slow Idle
Cab Window : Fully Open
Cooler Switch : ON
Airflow Volume : Maximum
Thermo Switch : Maximum

Inspection
After warm-up operation, carry out gas leak check
and performance check.

1. Check the air conditioner for gas leaks using a

leak tester. Leak Tester
(1) Perform checking under well-ventilated
conditions.
(2) Thoroughly wipe off dust from the charge
hose connections of the compressor.
(3) Pay special attention to check the line
connections.
(4) If any gas leaks are found, retighten the line
connections.

CAUTION: Refrigerant will produce W115-02-10-013

poisonous material if exposed to heat of
1000 °C (1800 °F) or more. Never bring
refrigerant close to a fire.

2. Performance Check
Carry out performance check of the air
conditioner after checking each air conditioner
component.
Retighten Line
(1) Check each component for abnormalities. Connection
(2) Carry out ON-OFF check of the compressor
clutch.
(3) Check compressor fan belt tension.
(4) Check the coolant level in the radiator.
(5) Operate the air conditioner and check the
W115-02-10-014
performance.

T5-4-93
 TROUBLESHOOTING / Troubleshooting B
3. The checklist before the summer season is as
follows:
(1) Check each air conditioner component for
abnormalities.
(2) Check the line connections for oil leaks.
(3) Check refrigerant quantity.
(4) Check the engine cooling circuit.
(5) Check belts for wear. Replace if necessary.

4. Off-Season Maintenance
(1) During off-season, operate the idler pulley
and compressor at least once a month for a
short time to check for any abnormal
sounds.
(2) Do not remove the compressor belts during
off-season. Operate the compressor
occasionally at slow speed for 5 to 10
minutes with the belt slightly loosened in
order to lubricate the machine parts.

T5-4-94
 TROUBLESHOOTING / Troubleshooting B
EXCHANGE INSPECTION
Exchange inspection method is a troubleshooting
method to find the trouble location by exchanging the
5P
suspected part / component with another part
/component having identical characteristics.
4P
Many sensors and solenoid valves used on this ma-
chine are identical. Therefore, using this switch-check
method, faulty part /component, and/or harness can
be easily found.

Example: Abnormal pump 1 delivery pressure (Fault

code:10)

Check Method:
1. Switch two delivery pressure sensors located as
shown in figure A to figure B.
2. Retry troubleshooting.
Pump 1
Pump 2
Result: (5-Spool
(4-Spool
Section)
In case the pump 2 delivery pressure is abnormal Section)
(fault code 11), the pump 1 delivery pressure sensor is Figure A
T16J-05-04-003
considered to be faulty.

In case the pump 1 delivery pressure is abnormal

(fault code 10), the pump 1 delivery pressure sensor
harness is considered to be faulty. 4P

5P

Pump 1
Pump 2 (4-Spool
(5-Spool Section)
Section)
Figure B
T16J-05-04-003

T5-4-95
 TROUBLESHOOTING / Troubleshooting B

Applicability of Switch-Check Method

Fault Code Trouble Cause
01 Abnormal EEPROM Not Applicable
02 Abnormal RAM
03 Abnormal A/D Conversion
04 Abnormal Sensor Voltage
05 Abnormal N Sensor Not Applicable
06 Abnormal EC Sensor Not Applicable
07 Abnormal Engine Control Dial Angle Not Applicable
08 Abnormal Pump 1 Displacement Angle Applicable (Sensor)
09 Abnormal Pump 2 Displacement Angle
10 Abnormal Pump 1 Delivery Pressure Applicable (Sensor)
11 Abnormal Pump 2 Delivery Pressure
12 Abnormal Pump1 Pump Control Pressure Applicable (Harness / Sensor)
13 Abnormal Pump2 Pump Control Pressure
14 Abnormal Swing Pilot Pressure Applicable (Harness / Sensor)
15 Abnormal Boom Raise Pilot Pressure
16 Abnormal Arm Roll-In Pilot Pressure
18 Abnormal Travel Pilot Pressure
19 Abnormal Hydraulic Oil Temperature Not Applicable
20 Pump1 Control Malfunction Appreciable (Solenoid Valve)
21 Pump2 Control Malfunction

T5-4-96
 TROUBLESHOOTING / Troubleshooting C
TROUBLESHOOTING C (TROUBLE-
SHOOTING FOR MONITOR) PROCEDURE
Use troubleshooting C when any monitors, such as
gauges or indicators malfunction.

• How to Read Troubleshooting Flow Charts

YES(OK)
(2)
After completing the checking and/or measuring procedures in box
・ (1) (1), select YES (OK) or NO (NOT OK) and proceed to box (2) or (3).

(3)
NO(NOT OK)

・ Instructions, reference, and/or instruction methods on inspection and/or measurements

are occasionally described under the box. If incorrectly checked or measured, not only
· Key switch: ON will troubleshooting be unsuccessful but also damage to components may result.

・ Causes of machine problems are stated in the thick-line box. Scanning quickly through
the thick-line boxes, allows you to estimate the possible causes before actually following
the flow chart.

NOTE: All harness end connector are seen from

the open end side.

Wire Harness Side

Open End
Side Harness End Connector

T158-05-03-001

T5-5-1
 TROUBLESHOOTING / Troubleshooting C
MALFUNCTION OF COOLANT TEM-
PERATURE GAUGE
• Check for loose harness connections beforehand.

YES

Disconnect coolant temperature

Gauge pointer doesn’t move sensor. Ground harness end
terminal to vehicle frame. Check Without connecting coolant
at all. temperature sensor, remove
if pointer swings to (H) side.
connector B (20P) from moni-
· Key switch: ON tor. Check for continuity be-
NO tween monitor harness end
connector terminal #18 and
coolant temperature sensor
terminal.

YES

Disconnect coolant tempera-

Gauge pointer swings over ture sensor. Check if pointer
scale. Without connecting coolant
returns to zero.
temperature sensor, remove
· Key switch: ON connector B (20P) from moni-
tor. Check for continuity be-
NO tween monitor harness end
terminal #18 and vehicle
frame.

YES

Disconnect coolant tempera-

ture sensor. Ground harness
Gauge pointer keeps moving end terminal to vehicle frame,
unstably. Check if pointer swings and is
stabilized to (H) side.
· Key switch: ON
NO

T5-5-2
 TROUBLESHOOTING / Troubleshooting C

Coolant Temperature Gauge

105 ﾟC
(95 ﾟC)
Faulty coolant temperature
sensor.

70 ﾟC

YES Faulty monitor.

T157-07-05-001
Broken harness between
NO monitor and sensor.

Coolant Temperature Sensor

Coolant Temperature Resistance (kΩ)
°C (°F)
25 (77) 7.6
Faulty coolant temperature 40 (104) 4.0±0.32
sensor.
50 (122) 2.7±0.216
80 (176) 0.98
95 (203) 0.6
YES Short-circuited harness be- 105 (221) 0.45
tween monitor and sensor. 120 (248) 0.3±0.015

Faulty monitor.
NO

Connector (Harness end connector terminals seen

Faulty coolant temperature
from the open end side)
sensor.
Monitor Connector B (20P)

10 9 8 7 6 5 4 3 2 1
20 19 18 17 16 15 14 13 12 11

Faulty monitor.

T5-5-3
 TROUBLESHOOTING / Troubleshooting C
MALFUNCTION OF FUEL GAUGE
• Check for loose harness connections beforehand.

YES

Disconnect fuel sensor. Con-

nect harness end connector
Fuel gauge pointer doesn’t terminal #1 to terminal #2 using
move at all. jumper wire such as clip. Check
Without connecting fuel sensor,
if pointer swings to (FULL) side.
remove connector B (20P) from
· Key switch: ON monitor. Check for continuity
NO between monitor terminal #19
and fuel sensor terminal 1.

YES

Fuel gauge pointer swings over Disconnect fuel sensor. Check

scale. if pointer returns to zero.
Without connecting fuel sensor,
· Key switch: ON remove connector B (20P) from
monitor. Check for continuity
NO between monitor harness end
terminal #19 and vehicle frame.

YES

Disconnect fuel sensor. Con-

nect harness end connector
Fuel gauge pointer keeps mov- terminal #1 to terminal #2 using
ing unstably. jumper wire such as clip. Check
if pointer swings and is stabi-
lized to (FULL) side.
· Key switch: ON NO

T5-5-4
 TROUBLESHOOTING / Troubleshooting C

Fuel Sensor

Float
Faulty fuel sensor.
FULL

R370
YES Faulty monitor. 257 mm 3/4

93 mm

Broken harness between 70.5 mm

NO monitor and sensor.
204 mm 1/2

338 mm 1/4

EMPTY
Faulty fuel sensor.
T178-05-05-001

NOTE: 1 mm = 0.03937 in
YES Short-circuited harness be- Float Position Resistance (Ω)
tween monitor and sensor. +0
Upper Limit (FULL) 10 -4
3/4 26
1/2 38±5
Faulty monitor. 1/4 53
NO Warning Level 85±3
+10
Lower Limit (EMPTY) 90 -0

Connector (Harness end connector terminals seen

from the open end side)
Faulty fuel sensor.
Monitor Connector B (20P) Fuel Sensor

10 9 8 7 6 5 4 3 2 1
20 19 18 17 16 15 14 13 12 11 1 2

Faulty monitor.

T5-5-5
 TROUBLESHOOTING / Troubleshooting C
MALFUNCTION OF INDICATOR LIGHT
CHECK SYSTEM
Check power line.
• Check for loose harness connections beforehand. ⋅ Fuse
YES ⋅ Remove connector C (20P)
from monitor. Check for con-
tinuity between harness end
terminal #1 and fuse terminal
Indicator doesn’t light when #7.
Check if all indicators don’t
indicator light check operation
light.
is performed.

Troubleshoot unlit indicator

NO individually.
Connector (Harness end connector terminals seen
from the open end side)

Monitor Connector C (20P)

10 9 8 7 6 5 4 3 2 1
20 19 18 17 16 15 14 13 12 11

T5-5-6
 TROUBLESHOOTING / Troubleshooting C
MALFUNCTION OF PREHEAT INDICATOR
• The preheat system operates only when coolant
temperature is below 10 °C (50 °F), lighting the
preheat indicator for 8 seconds. (Refer to the
SYSTEM /Electrical Circuit group.)
• In case the preheat system malfunctions, refer to
the troubleshooting B for “Engine is difficult to
start at low temperature”.
• Check for loose harness connections beforehand.

Faulty coolant
YES
temperature
switch.
Remove connector
Preheat indicator
(with blue cables)
lights even though YES Faulty QOS con-
from coolant tem-
preheat system troller.
perature switch.
doesn’t operate
Check if indicator
(coolant tempera-
goes OFF by
ture is more than Without connecting
grounding harness
10 °C (50 °F)). Disconnect QOS QOS controller,
Short-circuited
end connector to YES harness between
vehicle frame. controller. Check if remove connector
QOS controller
· Key switch: ON NO indicator goes B (20P) from moni-
OFF. and monitor.
tor. Check for con-
· Key switch: ON NO tinuity between
monitor harness
end connector Faulty monitor.
terminal #20 and NO
vehicle frame.

Faulty coolant
YES
temperature
switch.
Preheat indicator
doesn’t light al- Remove connector YES Faulty QOS con-
though preheat (with blue cables)
troller.
system operates from coolant tem-
(coolant tempera- perature switch.
Check if indicator Disconnect QOS
ture is lower than
comes ON. controller. Check if
10 °C (50 °F)). Broken harness
indicator comes YES
· Key switch: ON between QOS
ON by grounding Ground monitor
NO harness end con- controller and
connector B (20P)
monitor.
nector terminal #6 terminal #20 to ve-
to vehicle frame. NO hicle frame. Check
if indicator comes
· Key switch: ON Faulty monitor.
ON.
NO
· Without discon-
necting connector,
ground connector
to vehicle frame
Connector (Harness end connector terminals seen using jumper wire
from the open end side) such as clip from
reverse side of
Monitor Connector B (20P) QOS Controller connector.

10 9 8 7 6 5 4 3 2 1 1 2 3
20 19 18 17 16 15 14 13 12 11 4 5 6

T5-5-7
 TROUBLESHOOTING / Troubleshooting C
MALFUNCTION OF ENGINE OIL LEVEL
INDICATOR
• Check that indicator light is not burned out.
• Check that all other indicators work correctly.
• Check that machine is parked on level surface.
• Check for loose harness connections beforehand.

Without connecting
connector to engine oil YES
level switch, remove
connector B (20P)
NO from monitor. Check
for continuity between
Check if indicator monitor harness end
Indicator doesn’t lights by removing connector terminal #8
light even if engine NO
connector (with and vehicle frame.
oil level is lower black and white ca-
than specification. ble) from engine oil
level switch.

YES

Without connecting
connector to engine oil
level switch, remove
connector B (20P)
NO from monitor. Check
Remove connector for continuity between
Lower than 8.4 mm (with black and white
below LOW level mark monitor harness end
cables) from engine oil connector terminal #8
on oil level gauge level switch. Check if and engine oil level
indicator goes OFF by switch connector.
grounding harness
end connector to vehi-
Indicator comes ON
cle frame.
even if engine oil Check oil level with YES
level matches oil level gauge.
specification.

Above 8.4 mm
below LOW level mark
on oil level gauge

T5-5-8
 TROUBLESHOOTING / Troubleshooting C

Engine Oil Level Switch

Short-circuited harness be-
tween engine oil level switch
Oil Level
and monitor. Gauge Engine Oil Level
Switch

Faulty monitor. ON
H A
(Indicator ON)
L

Faulty engine oil level switch. (Indicator OFF)

OFF
A: 8.4 mm (0.33 in)

T107-04-03-010

YES Faulty monitor.

Broken harness between en-

gine oil level switch and moni- Connector (Harness end connector terminals seen
NO tor.
from the open end side)

Faulty engine oil level switch. Monitor Connector B (20P)

10 9 8 7 6 5 4 3 2 1
20 19 18 17 16 15 14 13 12 11

Normal (Lack of engine oil).

T5-5-9
 TROUBLESHOOTING / Troubleshooting C
MALFUNCTION OF COOLANT LEVEL IN-
DICATOR
• Check that indicator light is not burned out.
• Check that all other indicators work correctly.
• Check that machine is parked on level surface.
• Check for loose harness connections beforehand.

Without connecting
connector to coolant YES
level switch, remove
connector B (20P)
NO
from monitor. Check
for continuity between
Check if indicator monitor harness end
Indicator doesn’t
lights by removing connector terminal #9 NO
light even if coolant
connector (with blue and vehicle frame.
level is lower than
cable) from coolant
specification.
level switch.

YES

Without connecting
connector to coolant
level switch, remove
connector B (20P)
NO from monitor. Check
Remove connector for continuity between
(with blue cables) from monitor harness end
coolant level switch. connector terminal #9
NO Check if indicator goes and coolant level
OFF by grounding switch connector.
harness end connec-
Indicator comes ON Check if coolant tor terminal #1 to vehi-
even if coolant level level in coolant res- cle frame.
YES
matches specifica- ervoir is lower than
tion. LOW mark.

YES

T5-5-10
 TROUBLESHOOTING / Troubleshooting C

Short-circuited harness be- Coolant Level Switch

tween coolant level switch and
monitor.
Reservoir

Faulty monitor. ON
FULL

LOW
Faulty coolant level switch.
Radiator
OFF

Coolant Level Switch

T107-04-03-012

YES Faulty monitor.

Broken harness between

coolant level switch and moni-
NO tor. Connector (Harness end connector terminals seen
from the open end side)

Faulty coolant level switch.

Coolant Level Switch
Monitor Connector B (20P)

10 9 8 7 6 5 4 3 2 1
20 19 18 17 16 15 14 13 12 11 1 2
Normal (Lack of coolant).

T5-5-11
 TROUBLESHOOTING / Troubleshooting C
MALFUNCTION OF ALTERNATOR INDI-
CATOR
• Check for loose harness connections beforehand.

NOTE: Regulator terminals L are water-resistant

type connectors so that it is not practical to
measure voltage at these terminals. Meas-
ure voltage at starter relay terminal R in-
stead. Check for continuity between starter
relay terminal R and regulator terminal L
beforehand.

Between 13 V
and 33.5 V
Between 13 V
and 33.5 V Measure voltage at
monitor connector A
(16P) terminal #2.
Alternator indicator · Engine: Running Less than 13 V or
Measure voltage at
stays ON after en- regulator terminal L.
∗
higher than 33.5 V
gine is started.
· Engine: Running

Less than 13 V or
higher than 33.5 V

Between 10 V
and 33.5 V

YES Measure voltage at

regulator terminal L.
· Key switch: ON
Although alternator · Engine: Stopped
Check if indicator Less than 10 V or
output is low, alter-
lights when key higher than 33.5 V
nator indicator
switch is turned ON.
doesn’t light.
· Key switch: ON

NO

T5-5-12
TROUBLESHOOTING / Troubleshooting C

Connector (Harness end connector terminals seen

Faulty monitor. from the open end side)

Starter Relay

Broken harness between E

regulator terminal L and moni-
S R
tor.

Faulty regulator or alternator.

Monitor Connector A (16P)

8 7 6 5 4 3 2 1
16 15 14 13 12 11 10 9

Faulty monitor.

Faulty regulator.

Burned indicator light.

T5-5-13
 TROUBLESHOOTING / Troubleshooting C
MALFUNCTION OF ENGINE OIL PRES-
SURE INDICATOR
• Check for loose harness connections beforehand.

NOTE: During one or two minutes after the engine

is stopped, engine oil pressure may still
exist. When the engine is restarted under
this condition, the indicator may not light.
YES
Disconnect engine oil
pressure switch. Check
if indicator light when
YES
harness end connector
terminal #1 (white and Reconnect engine oil pres-
red cable) is grounded sure switch. Check if indica-
to vehicle frame. tor lights when monitor con-
Indicator doesn’t Check if indicator · Key switch: ON NO nector C (20P) terminal #18
light even if engine lights when key is grounded to vehicle frame.
oil pressure is low. switch is turned ON.
· Key switch: ON
· Key switch: ON · Without disconnecting con-
· Engine: Stopped nector, ground connector to
vehicle frame using such
jumper wire as clip from re-
verse side of connector.

NO

YES

Check if indicator
Indicator stays ON goes OFF when
after engine is engine oil pressure YES
Reconnect engine oil
started. switch is discon-
pressure switch and
nected.
· Check oil filter for remove connector C
clogging. · Key switch: ON (20P) from monitor.
· Engine: Stopped NO Check for continuity
between harness end
connector terminal #18
and vehicle frame.
NO

T5-5-14
 TROUBLESHOOTING / Troubleshooting C

Engine Oil Pressure Switch

Pressure Operation
Approx. 98 kPa
Faulty engine oil pressure 2
(1.0 kgf/cm , 14.22 psi) ON
switch. or less
Approx. 98 kPa
2
(1.0 kgf/cm , 14.22 psi) OFF
YES Broken harness between
monitor and engine oil pres- or higher
sure switch.

Faulty monitor.
NO

Burned indicator light.

Connector (Harness end connector terminals seen
from the open end side)

Monitor Connector C (20P)

Faulty engine oil pressure 10 9 8 7 6 5 4 3 2 1

switch or engine oil pressure 20 19 18 17 16 15 14 13 12 11
system, or clogged oil filter.

Engine Oil Pressure Switch

Short-circuited harness be-
tween monitor and engine oil
pressure switch. 1 2

Faulty monitor.

T5-5-15
 TROUBLESHOOTING / Troubleshooting C
MALFUNCTION OF OVERHEAT INDICA-
TOR
• Check for loose harness connections beforehand.

YES
Remove connector
(red and blue cable)
from overheat switch
YES (105 °C). Check if in-
dicator lights when har-
·ness
Key end terminal
Switch: ON is
grounded to vehicle
frame.
· Key switch: ON NO

Indicator doesn’t light Check if indicator

even if engine over- lights when key
heats. switch is turned ON.
· Key switch: ON

NO

YES

Check if indicator
Indicator lights even goes OFF when
if coolant tempera- overheat switch
ture is low. (105 °C) is discon-
nected. Disconnect overheat YES
· Key switch: ON switch (105 °C). Re-
· Engine: Stopped move connector B
(20P) from monitor.
NO
Check for continuity
between connector
terminal #6 and vehicle
frame.
NO

T5-5-16
 TROUBLESHOOTING / Troubleshooting C

Overheat Switch
Faulty overheat switch Coolant Temperature Operation
(105 °C). Lower than 105 °C OFF
(221 °F)
105 °C (221 °F) or ON
higher
Reconnect overheat YES Broken harness between
monitor and overheat
switch. Check if indi-
switch (105 °C).
cator lights when
monitor connector B
(20P) terminal #6 is
grounded to vehicle Faulty monitor.
frame. NO
· Key switch: ON
· Without disconnect-
ing connector, Connector (Harness end connector terminals seen
ground connector to
Monitor Connector B (20P)
vehicle frame using
such jumper wire as
clip from reverse side 10 9 8 7 6 5 4 3 2 1
of connector. 20 19 18 17 16 15 14 13 12 11
Burned indicator light.

Faulty overheat switch

(105 °C).

Short-circuited harness
between monitor and
overheat switch (105 °C).

Faulty monitor.

Overheat Switch
(105℃)
T17V-01-02-027

T5-5-17
 TROUBLESHOOTING / Troubleshooting C
MALFUNCTION OF AIR FILTER RESTRIC-
TION INDICATOR
• Check for loose harness connections beforehand.

YES
Disconnect air filter re-
striction switch at plug
receptacle with green
YES and blue cable. Check if
indicator lights when Reconnect air filter re-
harness end plug con- striction switch. Remove
nector is grounded to connector B (20P) from
vehicle frame. monitor. Check for conti-
Even if air filter is Check if indicator NO nuity between monitor
clogged, indicator lights when key · Key switch: ON
harness end connector
doesn’t light. switch is turned ON. terminal #7 and vehicle
· Key switch: ON f

NO

YES

Although air filter is Check if indicator

Disconnect air filter re-
not clogged, indi- goes OFF when air YES
striction switch at plug
cator lights. filter restriction switch
receptacle with green
is disconnected.
and blue cable and re-
· Disassemble and
· Key switch: ON move connector B (20P)
visually inspect.
from monitor. Check for
· Verify that air filter NO continuity between con-
is not moist.
nector terminal #7 and
vehicle frame.
NO

T5-5-18
 TROUBLESHOOTING / Troubleshooting C

Faulty air filter restriction

switch.
Air Filter Restriction Switch
Pressure Operation
YES Faulty monitor. 5.0 kPa (508 mmH2O) ON

Broken harness between

monitor and air filter re-
NO striction switch.

Burned indicator light.

Connector (Harness end connector terminals seen

Monitor Connector B (20P)

10 9 8 7 6 5 4 3 2 1
20 19 18 17 16 15 14 13 12 11

Faulty air filter restriction

switch.

Short-circuited harness
between monitor and air
filter restriction switch.

Faulty monitor.

T5-5-19
 TROUBLESHOOTING / Troubleshooting C
MALFUNCTION OF BUZZER
• Check for loose harness connections beforehand.

NOTE: Regulator terminals L are water-resistant

type connectors so that it is not practical to
measure voltage at these terminals. Meas-
ure voltage at starter relay terminal R in-
stead. Check for continuity between starter
relay terminal R and regulator terminal L
beforehand.

13 V or more Faulty regulator.

Buzzer continues to
sound when key Measure voltage at
switch is turned ON monitor connector A
without starting en- (16P) terminal #2.
gine. · Key switch: ON Faulty monitor.
(without starting Less than 13
engine)

YES Faulty engine oil pres-

sure system.
Buzzer continues to Check if engine oil
sound when engine pressure indicator YES Overheat of engine.
is started. lights.
Check if overheat in-
NO dicator lights.
Faulty monitor.
NO

NO Normal.
Buzzer doesn’t
sound even if en- Check if engine
gine oil pressure speed is 900 min
-1
NO Perform troubleshooting
indicator or over- (rpm) or faster. of indicator staying ON.
heat indicator lights
with engine running. Check if alternator in-
YES dicator lights.
Measure voltage at regu-
YES lator terminal L.
-1
· Engine speed: 900 min
(rpm) or faster

T5-5-20
 TROUBLESHOOTING / Troubleshooting C

Connector (Harness end connector terminals seen

from the open end side)

Monitor Connector A (16P) Starter Relay

8 7 6 5 4 3 2 1 E
16 15 14 13 12 11 10 9 S R

Lower than 13 V or
more than 33.5 V Faulty regulator and alterna-
tor.

Lower than 13 V or
higher than 33.5 V Broken harness between
regulator terminal L and moni-
tor.
Measure voltage at monitor
connector A (16P) terminal #2.
Between 13 V Faulty monitor.
and 33.5 V · Engine speed: 900
-1
min (rpm) or faster Between 13 V
and 33.5 V

T5-5-21
 TROUBLESHOOTING / Troubleshooting C
MALFUNCTION OF LCD
• The following items are described:
1 to 3: To be displayed in the standard mode.
4 to 8: To be displayed in the user’s mode.
9 to 23: To be displayed with built-in diagnosing
system
• In case only LCD is abnormal, the machine will
normally operate.

Display
Description Cause of Trouble
Order
1 Hour Meter Refer to the next page.
2 Trip 1 Faulty Monitor
3 Trip 2
4 Actual Engine Speed In case Dr. EX can display data, monitor is abnormal or communication
5 Hydraulic Oil Tempera- between monitor and MC is interrupted. In case Dr. EX doesn’t display
ture data, corresponding signal sensor is faulty. (The machine must have
any abnormality in the control system. Refer to Troubleshooting B.)
6 Not Operate
7
8 Fault Code In case Dr. EX can display data, monitor is abnormal or communication
9 between monitor and MC is interrupted. In case Dr. EX doesn’t display
10 Pump 1 Delivery Pres- data, corresponding signal sensor is faulty. (The machine must have
sure any abnormality in the control system. Refer to Troubleshooting B.)
11 Pump 2 Delivery Pres-
sure
12 Pump 1 Control Pres-
sure
13 Pump 2 Control Pres-
sure
14 Target Engine Speed
15 EC Angle
16 Dial Angle
17 Boom Raise Lever
Stroke
18 Arm Roll-In Lever Stroke
19 Swing Lever Stroke
20 Travel Lever Stroke
21 Bucket Lever Stroke
22 Attachment Lever Stroke
23 Work Mode

T5-5-22
 TROUBLESHOOTING / Troubleshooting C
MALFUNCTION OF HOUR METER
• Check for loose harness connections beforehand.
∗
NOTE: Regulator terminals L are water-resistant
type connectors so that it is not practical to
measure voltage at these terminals. Meas-
ure voltage at starter relay terminal R in-
stead. Check for continuity between starter
relay terminal R and regulator terminal L
beforehand.

Lower than 13 V or
higher than 33. V Faulty regulator or
alternator.
Hour meter
doesn’t count Between 13V
Measure voltage at
operating hours ∗ and 33.5 V Faulty monitor.
regulator terminal L.
with engine run-
-1
ning. · Engine speed: 900 min Measure voltage
· Engine: Running (rpm) or faster at monitor con-
Between 13V nector A (16P)
and 33.5 V terminal #2. Broken harness be-
tween regulator ter-
Lower than 13 V or minal L and monitor.
higher than 33. V

Connector (Harness end connector terminals seen

from the open end side)

Monitor Connector A Starter Relay

E
8 7 6 5 4 3 2 1
16 15 14 13 12 11 10 9 S R

T5-5-23
 TROUBLESHOOTING / Troubleshooting C
(Blank)

T5-5-24
 TROUBLESHOOTING / Electrical System Inspection
PRECAUTIONS FOR INSPECTION AND
MAINTENANCE
1. Disconnect the power source.
Be sure to remove the negative terminals from
the batteries first when taking wire harnesses and
connectors off for repair or replacement work.
Failure to do so can result in damage to the wire
harnesses, fuses, and fusible links and, in some
cases, cause fire due to short circuiting.
2. Color coding of wire harnesses. Code Color Code Color
The color codes of the wire harnesses in the R Red W White
electrical system are shown inn the table onn the L Blue G Green
right. Or Orange Lg Light green
In cases on the design sheet where two colors Y Yellow B Black
are indicated for one wire, the left initial stands for Br Brown P Pink
the base color, while the right initial stands for the
Gr Gray V Violet
marking color.

NOTE: 1) Code BW indicates a black base wire

with white fine-line marking.
Right Wrong
2) Initials “O” and “Or” both stand for the
color orange.
3) Wires with longitudinal stripes printed on
them are not color coded. Be sure not to
confuse them with color coded wires.
T107-07-06-001

3. Precautions for connecting and disconnecting

terminal connectors.
1) When disconnecting harnesses, grasp them
by their connectors. Do not pull on the wire
itself. Be sure to release the lock first before
attempting to separate connectors, if a lock Right
is provided. (Refer to “Instructions for Rust
Disconnecting Connector” on page T5-6-3.) Wrong
2) Water-resistant connectors keep water out (Deformation)
so that if water enters them, water will not
easily drain from them. When checking
Wrong
water-resistant connectors, take extra care (Separation)
not to allow water to enter the connectors. In T107-07-06-002

case water should enter the connectors,

reconnect only after the connectors are
thoroughly dried.
3) Before connecting terminal connectors,
check that no terminals are bent or coming
off. In addition, as most connectors are
made of brass, check that no terminals are
rusting.
4) When connecting terminal connectors
provided with a lock, be sure to insert them
together until the lock “clicks.”

T5-6-1
 TROUBLESHOOTING / Electrical System Inspection
4. Precaution for using a circuit tester.
1) Before using a circuit tester, refer to the
instructions in the circuit tester manual.
Then, set the circuit tester to meet the object Wind a Piece of Wire Tester Probe
to be measured, voltage range and current
polarity.
2) Before starting the connector test, always
check the connector terminal numbers,
Sharpen the end of the Wire
referring to the circuit diagram. T107-07-06-003
When the connector size is very small, and
the standard probe size is too large to be
used for testing, wind a fine piece of
sharpened wire or a pin around the probe to
make the test easier.

T5-6-2
 TROUBLESHOOTING / Electrical System Inspection
INSTRUCTIONS FOR DISCONNECTING
CONNECTORS
• Push to Unlock and Separate Type

NOTE: Connectors will not be easily separated

even if the lock is pushed while being
pulled. Push the lock first before pulling the
connectors.
The lock is located on female side con-
nector (harness end side). T107-04-05-002

Locations of This Type Connector

Fuel Gauge N Sensor Engine Oil Level Switch Radio
Hydraulic Oil Level Switch EC Motor Coolant Level Switch Speaker
Horn EC Sensor Diode Learning Switch
Cab Harness Pump Delivery Pressure Sensor Key Switch Wiper
Pressure Sensor General Relay Engine Control Dial Monitor
Washer Solenoid Valve Pump Displacement Sensor

• Pull Up to Unlock and Separate Type

Locations of This Type Connector

Starter Relay

• Pull to Separate Type T107-04-05-003

IMPORTANT: Generally, the solenoid valve con-

nector has a lock. Always pull to
separate the connector only after
unlocking using a tool such as a
pair of needle nose pliers.

Locations of This Type Connector

Oil Temperature Sensor
Dr.EX T107-04-05-004

T5-6-3
 TROUBLESHOOTING / Electrical System Inspection
FUSE INSPECTION
Cracks in a fuse are so fine that it is very difficult or NOTE: All terminals located along the lengthwise
impossible to find by visual inspection. Use a tester to centerline of the fuse box are connected to
correctly inspect fuse continuity by following the in- the power source, while terminals located
structions described below. away from the center of the fuse box are
connected to loads (accessories). There-
1. Turn Key Switch ON fore, test all fuses in the same method ex-
When the key switch is turned ON, current from cept for the glow plug relay circuit fuse.
key switch terminal M activates the battery relay Check the glow plug relay circuit fuse with
so that electric power is supplied to all circuits the key switch turned to the ON position
except the glow plug relay circuit. (Refer to the then follow the procedure in step 3.
circuit diagram.)
2. Remove the fuse box cover. Set the tester volt-
age to meet the circuit specification to be meas-
ured. (Measurement Range: 0 to 30 V) 10 20
3. Ground the negative probe of the tester to the ve- 9 19
hicle frame. Touch the terminals located away
from the center of the fuse box with the positive 8 18
probe of the tester one at a time. When normal 7 17
continuity of a fuse is intact, the tester will indicate
20 to 25 volts (battery voltage). 6 16
5 15
4 14
3 13
2 12
1 11

M178-07-034

Fuse Fuse
Capacity Connected to Capacity Connected to
No. No.
1 5A Radio, Monitor ICX (Backup 11 20 A Work Light Relays (R3, R4, R5)
Power)
2 5A MC (Main Power) 12 10 A Wiper Relays (R7, R8, R9,
R10), Wiper Motor, Washer
Relay, Washer
3 10 A MC (EC Motor Power) 13 20 A Heater (Air Conditioner Unit)
4 10 A MC (Solenoid Valve Power) 14 5A Air Conditioner Unit
5 5A Travel Alarm 15 10 A Horn Relay
6 5A MC, ICX (Power ON Signal) 16 5A Radio
7 5A Switch Box 17 10 A Cigarette Lighter
8 15 A Lubricator 18 5A Room Light
9 10 A Optional 1 (Light, etc.) 19 10 A Auxiliary
10 5A Auto-Lubrication 20 5A QOS Controller, Glow Relay

T5-6-4
 TROUBLESHOOTING / Electrical System Inspection
FUSIBLE LINK INSPECTION AND RE-
PLACEMENT
Inspection

1. Visually check if fusible links have blown.

Replacement

1. Remove the negative cable from the battery.

2. Push (to unlock) and pull to disconnect fusible

link connector. Replace the fusible link.
Fusible Link M16J-07-062

3. Reconnect the negative cable to the battery.

Fusible Link

BATTERY VOLTAGE CHECK

1. Turn the key switch OFF. Check voltage between
the battery positive terminal and the vehicle. T111-04-05-015

Normal Voltage: 24 V

NOTE: If voltage is abnormal, recharge or replace

the battery.
To Battery Relay

2. Start the engine. Check voltage between the

battery positive terminal and the vehicle frame.

Normal Voltage: 26 to 28 V

NOTE: If voltage is abnormal, check the charging

system.
V

T162-05-06-005

T5-6-5
 TROUBLESHOOTING / Electrical System Inspection
HOW TO TROUBLESHOOT ALTERNATOR
MALFUNCTIONS
In general, the alternator indicator remains off when
the alternator is generating power.
If the alternator indicator comes on while the engine is
running, the alternator might be defective.

How to check the circuit

1. Stop the engine. Turn the key switch to the ON B Connector (L, R)
position. Confirm that the alternator indicator
comes on.

2. Measure the voltage between the B and the

alternator body. If the measured voltage is around
24 V, the alternator circuit can be considered
normal. If the measured voltage is low, a shortage
in battery capacity or looseness of the wire
connectors of the alternator circuit might be the
cause of the malfunction. When the voltage is 0 V,
the wiring between the fuse box and alternator
might be loose or disconnected.
Also, the alternator cannot generate electricity if
the ground line is disconnected.

3. Next, start the engine and measure the voltage

generated while as the alternator rotates.
T16J-05-06-001
As described above, measure the voltage
between terminals B and the alternator body. If
the voltage is around 28 V, the alternator is
operating normally.
If the rated voltage is not being generated, there
is some trouble with the alternator or the regula-
tor.

T5-6-6
 TROUBLESHOOTING / Electrical System Inspection
CONTINUITY CHECK
Harness
Single-line continuity check A a
Disconnect both end connectors of the harness and
check continuity between both ends:
If the ohm-meter reading is: 0 Ω = Continuity
∞ Ω = Discontinuity
Ω

NOTE: When the one end connector is far apart

from the other, connect one end of Connect to A a
connector (A) to the machine chassis using the vehicle
a clip. Then, check continuity of the frame.
harness through the vehicle frame as
illustrated.
Connect to Ω
the vehicle
If the ohm-meter reading is: 0 Ω = Continuity frame.
∞ Ω = Discontinuity
A a
Single-line short-circuit check
Disconnect both end connectors of the harness and × Short-circuit
check continuity between one end connector of the between the
harness and
harness and the vehicle frame: the vehicle
Ω frame
If the ohm-meter reading is:
0 Ω = Short circuit is present.
∞ Ω = No short circuit is present.
T107-07-05-003
Multi-line continuity check
Disconnect both end connectors of the harness, and First short-circuit
short-circuit two terminals, (A) and (B), at one end
connector, as illustrated. Then, check continuity
between terminals (a) and (b) at the other connector. A a
If the ohm-meter reading is ∞ Ω, either line (A) - (a), B b
C c
or (B) - (b) is in discontinuity. To find out which line is
discontinued, conduct the single line continuity
Second short-circuit
check on both lines individually, or, after changing
the short-circuit terminals from (A) - (B) to (A) - (C),
check continuity once more between terminals (a)
and (c). Ω

NOTE: By conducting the multi-line continuity

T107-07-05-004
check twice, it is possible to find out which
line is discontinued. With terminals (A) and Short-circuit between harnesses.
(C) short-circuited, check continuity
between terminals (a) and (c). A a
×
If the ohm-meter reading is: B b
0 Ω = Line (B) - (b) has discontinuity. C c
∞ Ω = Line (A) - (a) has discontinuity.

Multi-line short-circuit check

Disconnect both end connectors of the harness, and
check continuity between terminals (A) and (B) or Ω
(C).
If the ohm-meter reading is:
0 Ω = Short-circuit exists between the lines.
T107-07-05-005
∞ Ω = No short-circuit exists between the lines.

T5-6-7
 TROUBLESHOOTING / Electrical System Inspection
VOLTAGE AND CURRENT MEASURE-
MENT
Turn key switch ON so that the specified voltage (cur-
rent) is supplied to the location to be measured. Judge
if the circuit is normal by evaluating whether the
measured voltage (current) matches the specification.

24-Volt Circuit
Start checking the circuit in order up to the loca-
tion to be measured from either power source or
actuator side. Thereby, the faulty location in the
circuit will be found.
Black Probe (Minus) of Tester : To ground to the vehi-
cle frame
Red Probe (Plus) of Tester : To touch the location
to be measured
Engine Key Switch Location to be Measured Specification
Power Source Circuit
Stopped OFF Between (2) and (1): One Battery 10 to 12.5 V
Stopped OFF Between (3) and (2): One Battery 10 to 12.5 V
Stopped OFF Between (3) and (1): Two Batteries 20 to 25 V
Stopped OFF Between (4) and Ground: Battery Power 20 to 25 V
Stopped OFF Between (5) and Ground: Fusible Link 20 to 25 V
Stopped OFF Between (1) and Ground: Backup Current* 6 mA
Preheat Circuit
Stopped ON or START Between (6) and Ground: Key Switch 20 to 25 V
Stopped ON or START Between (7) and Ground: Glow Plug 20 to 25 V
Starting Circuit
Started START Between (8) and Ground: Key Switch 20 to 25 V
Started START Between (9) and Ground: Battery Relay (Coil) 20 to 25 V
Started START Between (10) and Ground: Battery Relay (Switch) 20 to 25 V
Started START Between (11) and Ground: Starter (B) 20 to 25 V
Started START Between (12) and Ground: Starter (C) 20 to 25 V
Started START Between (13) and Ground: Starter Relay (S) 20 to 25 V
Charging Circuit
Fast Speed ON Between (14) and Ground: Alternator Generating Voltage 26 to 30 V
(B)
Fast Speed ON Between (10) and Ground: Battery Relay / Generating 26 to 30 V
Voltage
Fast Speed ON Between (15) and Ground: Fuse Box / Generating Voltage 26 to 30 V
Fast Speed ON Between (16) and Ground: Generating Voltage 13 to 30 V
Fast Speed ON Between (17) and Ground: Monitor 13 to 30 V
Surge Voltage Pre-
vention Circuit
Slow Idling ON Between (14) and Ground: Alternator (B) 26 to 30 V
Slow Idling ON Between (16) and Ground: Starter Relay (R) 13 to 30 V
Slow Idling ON Between (18) and Ground: Load Damp Relay 26 to 30 V
Slow Idling ON Between (10) and Ground: Battery Relay 26 to 30 V
Accessory Circuit
Stopped ON Between (19) and Ground: Auxiliary 20 to 25 V
Stopped ON Between (20) and Ground: Room light 20 to 25 V
Stopped ON Between (21) and Ground: Cigar Lighter 20 to 25 V
Stopped ON Between (22) and Ground: Radio 20 to 25 V
Stopped ON Between (23) and Ground: Horn 20 to 25 V
Stopped ON Between (9) and Ground: Battery Relay 20 to 25 V
*Measure after disconnecting the negative cable from the battery.

T5-6-8
 TROUBLESHOOTING / Electrical System Inspection

Key Switch

Battery
1 2 3 5 4 9

6 8

15
Battery Relay

Starter 10 Fuse
B Box
C
11 Load
18
12 Damp
B Relay
S
E 23 22 21 20 19
13 17
Starter Relay R
16
Alternator
14
Monitor
Glow
Plug
Relay

Glow Plug

T16J-05-06-007

T5-6-9
 TROUBLESHOOTING / Electrical System Inspection
5 Voltage Circuit
Signal or
• Voltage between terminal No.1 and the vehicle Two polarities Power source ground
frame (ground) 1 2
With the key switch turned OFF, disconnect the
sensor connector.
Measure the voltage between terminal No.1 on the
machine harness side connector and the vehicle
(ground) under the following conditions.
V
• Key switch position: ON
• Tester black terminal (negative):
Connected to the vehicle (ground)
• Tester red terminal (positive):
T107-07-05-006
Connected to terminal No.1
Three polarities Power source Signal Ground
Evaluation: 1 2 3
If the measuring voltage is within 5±0.5 volts, the
circuit up to terminal No.1 is normal.

• Voltage between terminal No.1 and the ground T107-07-05-007

terminal
With the key switch turned OFF, disconnect the Two polarities
1 2
sensor connector.
Measure the voltage between terminal No.1 on the
machine harness side connector and the ground
terminal (terminal No.2 for two polarities, or terminal
No.3 for three polarities) under the following V
conditions.

• Key switch position: ON

• Tester black terminal (negative):
Connected to the ground terminal
(terminal No.2 or 3) T107-07-05-008
• Tester red terminal (positive):
Connected to terminal No.1 Three polarities
1 2 3
Evaluation:
If the measuring voltage is within 5±0.5 volts, the
circuit up to terminal No.1 or the ground terminal is
normal.
V

T107-07-05-009

T5-6-10
 TROUBLESHOOTING / Electrical System Inspection
CHECK BY FALSE SIGNAL
Two-Polarities
Turn the key switch OFF. After disconnecting the sen- (Oil Temperature)
sor connector, turn the key switch ON. Then, connect (N Sensor)
1 2
machine side harness end connector terminal #1
(power) to terminal #2 (signal). (Power voltage is used
as a false signal.) Check the controller using Dr. EX
monitor function under this condition. When the maxi-
mum value is displayed, the MC and the circuit up to
the machine side harness end connector are normal.
When the pressure switch circuits are normal, Dr. EX Connect
displays “ON.”

IMPORTANT: Don’t connect terminal #1 or #2 to

terminal #3 or to the vehicle frame Three Polarities
T107-07-05-010

(ground) when checking a

three-polarity connector. (Pressure Sensor)
(Pump Delivery Pressure Sensor)
(Pump Control Pressure Sensor) 1 2 3
NOTE: Some kinds of sensors can be monitored (EC Sensor)
by the built-in diagnosing system. (Refer to
the TROUBLESHOOTING / General
group.)

Connect

T107-07-05-011

T5-6-11
 TROUBLESHOOTING / Electrical System Inspection
TEST HARNESS
With a test harness installed between connectors, the
circuit condition is checked depending on whether the
test harness lamp lights or extinguishes during opera-
tion.

Parts Number 4283594 (ST 7126)

Use to check a single-line (discontinuity and/or volt-
age).
To Location to be measured.
During Operation: Lamp is ON. To Ground
T107-07-05-012
Parts Number 4283594 (ST 7126)

Parts Number (ST 7130)

Use to check the solenoid valve unit circuits.
When the corresponding control lever or switch is 4
3
operated: Lamp is ON.

1 2 2 1

Parts Number 4274589 (ST 7125)

Use to check the EC motor circuit. Parts Number (ST 7130) T16J-05-06-003

• EC Motor Circuit
When the engine control dial is rotated:
Both lamps ON: Normal 5
Only one lamp ON: Check for continuity of the 6
circuit connected to the lamp OFF. 50
Both lamps OFF: Check the harness together 1 2 2 1
150 50
with the relay. 50
4 3 4 3
7 50
8

Parts Number 4284347 (ST 7129) Parts Number 4274589 (ST 7125)
T107-07-06-024
Use to measure the EC sensor or pump displace-
ment sensor circuit signal line voltage (between ter-
minals #2 and #3).

(Red)

(Black)

Parts Number 4284347 (ST 7129) T107-07-03-009

T5-6-12
 TROUBLESHOOTING / Electrical System Inspection
Parts Number (ST 7227)
Use to check the wiper circuit.

2
5 1
2 4 7
1

Parts Number (ST 7227) T178-05-06-003

T5-6-13
 TROUBLESHOOTING / Electrical System Inspection
(Blank)

T5-6-14
 TROUBLESHOOTING / ICX
OUTLINE
The ICX (information controller) stores signals from
various kinds of sensors and switches provided on the
machine as data. The various input signals are
grouped into “Daily Report Data List”, “Frequency Dis-
tribution Data List”, “Cumulative Operation Hour List”,
“Alarm List”, and “Trouble List” and are recorded in the
ICX.

The machine equipped with the optional satellite

terminal which will send the data to the center server
via the satellite communication system.

T5-7-1
 TROUBLESHOOTING / ICX
Daily Report Data List

Data Details
1 Key Switch ON Time Time when key switch is first turned ON during daily opera-
tion
(Time is recorded by key switch ON signal.)
2 Key Switch OFF Time Time when key switch is last turned OFF during daily op-
eration
(Time is recorded by key switch ON signal.)
3 Engine Start Time Time when engine is first started during daily operation
(Time is recorded by alternator output signal.)
4 Engine Stop Time Time when engine is last stopped during daily operation
(Time is recorded by alternator output signal.)
5 Hour Meter Hour meter cumulative hours
(Hours are recorded by hour meter signal from monitor.)
6 Engine Operating Hours Total engine operating hours during daily operation
(Hours are recorded by alternator output signal.)
7 Swing Operating Hours Total swing operating hours during daily operation
(Hours are recorded by signals from swing pressure sen-
sor.)
8 Travel Operating Hours Total travel operating hours during daily operation
(Hours are recorded by signals from travel pressure sen-
sor.)
9 Front Attachment Operating Hours Total front attachment operating hours during daily opera-
tion
(Hours are recorded by signals from front attachment pres-
sure sensor.)
10 Breaker Operating Hours Total breaker operating hours during daily operation
Breaker Mode 1 : (Hours are recorded by signals from auxiliary pressure
sensor and attachment mode switch.)
11 Breaker operating Hours Total breaker operating hours during daily operation
Breaker Mode 2: (Hours are recorded by signals from auxiliary pressure sen-
Breaker Mode 3: sor and attachment mode switch.)
12 Engine Operating Hour Distribution Engine operating hour distribution during daily operation
(Operating hours are recorded only when alternator output
signal is continuously delivered for more than 10 minutes.)

NOTE: The daily operation in this table is equivalent

to the hours between 0:00 and 23:59:59
counted by the ICX built-in clock. In case
the engine is kept operated beyond 0:00,
such data are recorded as those for the fol-
lowing day.

T5-7-2
 TROUBLESHOOTING / ICX
Frequency Distribution Data List

Data Details
1 Engine Speeds Frequency distribution of engine speeds
(Speeds are recorded by signals from N sensor.)
2 Hydraulic Oil Temperature Frequency distribution of hydraulic oil temperature
(Temperatures are recorded by signals from oil tempera-
ture sensor.)
3 Coolant Temperature in Radiator Frequency distribution of coolant temperature
(Temperatures are recorded by signals from coolant tem-
perature sensor.)
4 Average Pump Delivery Pressure Frequency distribution of average delivery pressure from
pumps 1 and 2
(Average pressures are recorded by signals from delivery
pressure sensors of pumps 1 and 2.)
5 Average Pump Delivery Pressure in Digging Frequency distribution of average delivery pressure from
Operation pumps during digging operation
(Average pressures are recorded by signals from arm
roll-in pressure sensor.)
6 Average Pump Delivery Pressure in Travel Frequency distribution of average delivery pressure from
Operation pumps during travel operation
(Average pressures are recorded by signals from travel
pressure sensor.)

Cumulative Operation Hour List

Data Details
1 Engine Operation Hour Cumulative engine operation hours
(Hours are recorded by alternator output signal.)
2 Swing Operation Hour Cumulative swing operation hours
(Hours are recorded by signals from swing pressure sen-
sor.)
3 Travel Operation Hour Cumulative travel operation hours
(Hours are recorded by signals from travel pressure sen-
sor.)
4 Front Attachment Operation Hour Cumulative front attachment operation hours
(Hours are recorded by signals from front attachment
pressure sensor.)
5 Breaker Operating Hours Total breaker operating hours during daily operation
Breaker Mode 1 : (Hours are recorded by signals from auxiliary pressure
sensor and attachment mode switch.)
6 Breaker operating Hours Total breaker operating hours during daily operation
Breaker Mode 2: (Hours are recorded by signals from auxiliary pressure sen-
Breaker Mode 3: sor and attachment mode switch.)

T5-7-3
 TROUBLESHOOTING / ICX
Alarm List

Code Data Details

81 Engine Oil Level Date and time when engine oil level indicator lighted are recorded by
signals from engine oil level switch.
85 Coolant in Radiator Date and time when coolant level indicator lighted are recorded by
signals from coolant level switch.
86 Hydraulic Oil Filter Date and time when hydraulic oil filter indicator lighted are recorded
by signals from hydraulic oil filter restriction switch.
89 Overheat Date and time when overheat indicator lighted are recorded by sig-
nals from overheat switch.
90 Engine Oil Pressure Date and time when engine oil pressure indicator lighted are re-
corded by signals from engine oil pressure switch.
93 Air Filter Restriction Date and time when air filter restriction indicator lighted are recorded
by signals from air filter restriction switch.
94 Alternator Indicator Date and time when alternator indicator lighted are recorded by sig-
nals from monitor controller.

NOTE: In case the above alarms are recorded,

check individual item. If malfunction of the
monitor is found, refer to troubleshooting C.

T5-7-4
 TROUBLESHOOTING / ICX
Trouble List

Fault
Trouble Details
Code
01 Abnormal EEPROM Occurrence time and date of fault code 01
02 Abnormal RAM Occurrence time and date of fault code 02
03 Abnormal A/D Conversion Occurrence time and date of fault code 03
04 Abnormal Sensor Voltage Occurrence time and date of fault code 04
05 Abnormal Engine Speed Occurrence time and date of fault code 05
06 Abnormal EC Sensor Occurrence time and date of fault code 06
07 Abnormal Engine Control Dial Occurrence time and date of fault code 07
10 Abnormal Pump 1 Delivery Pressure Occurrence time and date of fault code 10
11 Abnormal Pump 2 Delivery Pressure Occurrence time and date of fault code 11
12 Abnormal Pump 1 Control Pressure Occurrence time and date of fault code 12
13 Abnormal Pump 2 Control Pressure Occurrence time and date of fault code 13
14 Abnormal Swing Lever Stroke Occurrence time and date of fault code 14
15 Abnormal Boom Raise Lever Stroke Occurrence time and date of fault code 15
16 Abnormal Arm Roll-In Lever Stroke Occurrence time and date of fault code 16
17 Abnormal Bucket Roll-In Lever Stroke Occurrence time and date of fault code 17
18 Abnormal Travel Lever Stroke Occurrence time and date of fault code 18
19 Abnormal Oil Temperature Sensor Occurrence time and date of fault code 19
20 Abnormal Pump 1 Control Malfunction Occurrence time and date of fault code 20
21 Abnormal Pump 2 Control Malfunction Occurrence time and date of fault code 21
64 MC Communication Error Time and date when communication error between MC
and ICX occurred.
65 Monitor Communication Error Time and date when communication error between
monitor and ICX occurred.
66 Satellite Terminal Communication Error Time and date when communication error between sat-
ellite terminal and ICX occurred.

NOTE: In case the above fault codes are recorded,

refer to troubleshooting A.

T5-7-5
 TROUBLESHOOTING / ICX
ICX FAULT CODE LIST

Fault
Trouble Remarks
Code
1 Abnormal Internal Ram In case of SAM error
2 Abnormal Flush Memory In case of SAM error
3 Abnormal Exterior In case of SAM error or read-write error
4 Abnormal EEPROM In case of SAM error
5 Overwritten Data Save Area In case data save area was overwritten.
6 Abnormal Time In case RTC data was other than figures.
7 MC Communication Timeout In case MC communication lasted for less than 100 ms.
8 Monitor Communication Timeout In case monitor communication didn’t last for more than
12 seconds.
9* MC Communication Timeout In case MC communication didn’t last for more than 20
seconds.
10 Satellite Terminal Communication Timeout In case satellite communication didn’t last for more than
20 seconds.

NOTE * Fault code 9 may be displayed on only the

machine to which the ICX is installed later.

SATELLITE TERMINAL FAULT CODE LIST

Fault
Trouble Remarks
Code
101 Satellite Terminal: Internal Error Abnormal EEPROM
102 Satellite Terminal: Internal Error Abnormal sent data
103 Satellite Terminal: Internal Error In case reception is difficult.
104 Satellite Terminal: Communication Error In case satellite communication cannot be accom-
plished.
105 Satellite Terminal: Internal Error In case sending retry over occurred or local loop back
test failed with power ON.
106 Satellite Terminal: Communication Error In case sending retry over occurred.
107 Satellite Terminal: Abnormal Harness In case reception data doesn’t match sending data.

T5-7-6
 TROUBLESHOOTING / ICX
FAULT CODE 1 TO 6

YES Faulty ICX

Check if all data are normally

cumulated.
Faulty ICX
NO
· Refer to T5-7-10 for replacing
*even if the fault code remains displayed after retrying, ICX.
the machine can be operated as it is when data re-
cord is normally cumulated.

FAULT CODE 7 TO 10

YES Faulty ICX

Check for continuity between
ICX and corresponding com- · Refer to T5-7-10 for replacing
ponent while referring to the ICX.
following table. Broken harness between ICX
and corresponding compo-
NO nent

Fault code ICX terminal # Corresponding component terminal #

7 Connector c terminal #11 Mc connector D terminal #10
8 Connector c terminal #12 Monitor connector B terminal #1
10 Connector b terminal #4 Satellite terminal

T5-7-7
 TROUBLESHOOTING / ICX
SOME PARTS OF DATA IN DAILY REPORT,
FREQUENCY DISTRIBUTION, CUMULA-
TIVE OPERATION HOURS ARE NOT RE-
CORDED
• All necessary data signals may not be input into
the ICX. Individual signals are utilized to record
more than one data. While referring to the table
below, check the corresponding system for any
abnormality.

Related Data Input Signal

Key switch ON and OFF time Key switch

Engine start and stop time, Engine operating hours (Daily report and cu- Alternator
mulative operation hour), Engine operating hour distribution
Hour meter Monitor controller

Coolant temperature distribution in radiator Coolant temperature sensor

Remaining fuel level (detected at regular data sending time) Fuel level sensor

Travel operating hours (Daily report and cumulative operation hour), Aver- Travel pressure sensor
age pump delivery pressure distribution in travel operation
Front attachment operating hours (Daily report and cumulative operation Front attachment ⋅ swing pressure
hour) sensor
Swing operating hours (Daily report and cumulative operation hour) Swing pressure sensor

Average pump delivery pressure distribution in digging operation Arm roll-in pressure sensor

Breaker operating hours (Daily report and cumulative operation hour), Aux- Auxiliary pressure sensor
iliary attachment except for breaker operating hours (Daily report and cu-
mulative operation hour)
Distribution of average pump delivery pressure, average pump delivery Pump 1 delivery pressure sensor
pressure in digging operation and travel operation
Distribution of average pump delivery pressure, average pump delivery Pump 2 delivery pressure sensor
pressure in digging operation and travel operation
Engine speed distribution N sensor

Breaker operating hours (Daily report and cumulative operation hour) Attachment mode switch

Breaker operating hours (Daily report and cumulative operation hour) Auxiliary mode switch

T5-7-8
 TROUBLESHOOTING / ICX

Corrective Action Remarks

Check harness between ICX terminal A5 and key In case engine doesn’t start, refer to troubleshooting B.
switch terminal M.
Check harness between ICX terminal A2 and alternator In case alternator indicator malfunctions, refer to trou-
terminal L. bleshooting C.
Check harness between ICX terminal C12 and monitor In case hour meter malfunctions, refer to troubleshoot-
terminal B1. ing C.
Check harness between ICX terminal C12 and monitor In case coolant temperature gauge malfunctions, refer
terminal B1. to troubleshooting C.
Check harness between ICX terminal C12 and monitor In case fuel gauge malfunctions, refer to troubleshoot-
terminal B1. ing C.
Check harness between ICX terminal C11 and MC ter- In case machine control system malfunctions, refer to
minal D10. troubleshooting B.
Check harness between ICX terminal C11 and MC ter- In case machine control system malfunctions, refer to
minal D10. troubleshooting B.
Check harness between ICX terminal C11 and MC ter- In case machine control system malfunctions, refer to
minal D10. troubleshooting B.
Check harness between ICX terminal C11 and MC ter- In case machine control system malfunctions, refer to
minal D10. troubleshooting B.
Check harness between ICX terminal C11 and MC ter- In case machine control system malfunctions, refer to
minal D10. troubleshooting B.
Check harness between ICX terminal C11 and MC ter- In case machine control system malfunctions, refer to
minal D10. troubleshooting B.
Check harness between ICX terminal C11 and MC ter- In case machine control system malfunctions, refer to
minal D10. troubleshooting B.
Check harness between ICX terminal C11 and MC ter- In case machine control system malfunctions, refer to
minal D10. troubleshooting B.
Check harness between ICX terminal C11 and MC ter- In case machine control system malfunctions, refer to
minal D10. troubleshooting B.
Check harness between ICX terminal C11 and MC ter- In case machine control system malfunctions, refer to
minal D10. troubleshooting B.

T5-7-9
 TROUBLESHOOTING / ICX
TROUBLESHOOTING AND SETTING OF
ICX AND SATELLITE TERMINAL USING
DR.EX
Troubleshooting of ICX can be performed using Dr.
EX.

IMPORTANT: As for the ICX setting, the setting

way is different according to the
version of software. Please contact
Hitachi Construction Machinery’s
Authorized Dealers.

T5-7-10
 TROUBLESHOOTING / ICX
SATELLITE COMMUNICATION SYSTEM
GPS Antenna
The satellite communication system is used for the
maintenance of the machine by transmitting various
data of the machine regularly via a low earth orbit sat-
ellite.

NOTE: Since the satellite communication system Communication

is available depending on region, contact Antenna
Hitachi Construction Machinery Co. Ltd.
International Product Support department
for details.
Depending on the circumstances of the
machine (ex. in the constructions, in the
tunnel, affected by the surrounding building
and affected of noise), the data transfer
rate may become slower, or the communi-
cation might not be established. M178-13-002

Also, the satellite communication system Mail Switch

using a low earth orbit satellite transmits
digital data through the radio wave. If there
is excessively noise or use of electrical
equipment which caused noise placed near
the machine, they cause reduces data
transfer rate or communication might not
be established at worst.

The satellite communication system is composed of:

Satellite terminal, GPS antenna, communication an-
tenna and mail switch. The functions of each equip-
ment are: M178-01-141

• Satellite Terminal Satellite Terminal

It receives the data from ICX, GPS antenna and
mail switch, and send the data to the communica-
tion antenna.
• GPS Antenna
It receives the location information of the machine
from a low earth orbit satellite.
• Communication Antenna
It communicates the data with a low earth orbit
satellite.
• Mail Switch
It sends date and time information, latest location
of the machine and the fuel level (%) when the
switch is pressed.

T178-01-02-006

T5-7-11
 TROUBLESHOOTING / ICX
On the machine equipped with the satellite communi-
cation system, the data are sent according to the con-
dition as follows:

Kinds of data sent from the machine by satellite com-

munication:
Items Kinds of Data Condition
Periodical Operation Record, Latest Location Infor- The data are transmitted once every day.
Transmission mation, Fuel Level To avoid congested traffic in the commu-
nication line, the data is transmitted ran-
domly between 0:00 and 02:00.
Transmitting Data at Latest Location Information The data is transmitted only when the
Engine Start machine is moved more than 5 km from
the place where it is recorded lastly.
Emergency Alarm and Error Information The transmission starts immediately
Transmission when the alarm and error occurs.
Hour Meter 100 Hours Frequency Distribution Information The data is transmitted when the hour
Transmission meter exceeds every 100 hours.
Transmission by Mail Date and time when the switch is pressed, The transmission starts immediately
Switch Latest location of the machine, Fuel level when the mail switch is pressed.

T5-7-12
 MEMO

....................................................................................................................................................................

....................................................................................................................................................................

....................................................................................................................................................................

....................................................................................................................................................................

....................................................................................................................................................................

....................................................................................................................................................................

....................................................................................................................................................................

....................................................................................................................................................................

....................................................................................................................................................................

....................................................................................................................................................................

....................................................................................................................................................................

....................................................................................................................................................................

....................................................................................................................................................................

....................................................................................................................................................................

....................................................................................................................................................................

....................................................................................................................................................................

....................................................................................................................................................................

....................................................................................................................................................................

....................................................................................................................................................................

....................................................................................................................................................................

....................................................................................................................................................................

....................................................................................................................................................................

....................................................................................................................................................................

....................................................................................................................................................................

....................................................................................................................................................................

....................................................................................................................................................................

....................................................................................................................................................................

....................................................................................................................................................................

....................................................................................................................................................................

....................................................................................................................................................................
 MEMO

....................................................................................................................................................................

....................................................................................................................................................................

....................................................................................................................................................................

....................................................................................................................................................................

....................................................................................................................................................................

....................................................................................................................................................................

....................................................................................................................................................................

....................................................................................................................................................................

....................................................................................................................................................................

....................................................................................................................................................................

....................................................................................................................................................................

....................................................................................................................................................................

....................................................................................................................................................................

....................................................................................................................................................................

....................................................................................................................................................................

....................................................................................................................................................................

....................................................................................................................................................................

....................................................................................................................................................................

....................................................................................................................................................................

....................................................................................................................................................................

....................................................................................................................................................................

....................................................................................................................................................................

....................................................................................................................................................................

....................................................................................................................................................................

....................................................................................................................................................................

....................................................................................................................................................................

....................................................................................................................................................................

....................................................................................................................................................................

....................................................................................................................................................................

....................................................................................................................................................................
Hitachi Construction Machinery Co. Ltd Hitachi Ref. No.
Attn: Publications, Marketing & Product Support
Fax: 81-298-31-1162

SERVICE MANUAL REVISION REQUEST FORM

NAME OF COMPANY: MODEL:

PUBLECATION NO.:
YOUR NAME: (Located at the left bottom corner in the cover page)

PAGE NO.:
DATE: (Located at the bottom center in the page. If two or more
revisions are requested, use the comment column)
FAX:

YOUR COMMENTS / SUGGESTIONS:

Attach photo or sketch is required.
If your need more space, please use another sheet.

REPLY:

(Copy this form for usage)

 THE ATTACHED DIAGRAM LIST

(The following diagrams are attached to this manual.)

1 ELECTRICAL CIRCUIT DIAGRAM CONNECTORS

2 CAB HARNESS ENGINE HARNESS
3 MONITOR HARNESS
4 HYDRAULIC CIRCUIT DIAGRAM